Excellent set of towers
I've never had issues with any Yakima towers, and these were no exception. All 4 worked great for my ski trip to Colorado this year, and were easy to install. I highly recommend buying from Amazon, because I priced Yakima equipment from a local store in town, and I saved over 0 on my total package between the Towers, Crossbars, Lock Cores and Carrier.

Round bars suck - wish I bought another Thule roof rack
While the Q-Towers do seem to fit my roof very well, I have not yet figured out exactly what part of the Yakima clips or Q-towers is scratching the roof of my car. When I do, hopefully I will be able to do something to cover the sharp edges. It's not a single spot on the clip, because several times I got these sets of parallel scratches almost like you'd picture from cat's claws (and in this case, that would be a very big cat!).

Also the Yakima Q-towers have these clear gel-like pads that protect the roof of the car, and unfortunately at least one always seems to want to come loose and fall off when I have the rack stored in my garage or when I'm lifting it into place. I never had this problem with the black pads on my old Thule towers which were firmly and permanently attached to the feet.

The Yakima clips specific to my car: There is thick adhesive black "tape" which you put over the feet of the clips. This is already coming off the clips only a few months after I put it on. By contrast, the ends of the clips on my Thule roof rack were dipped in something like heavy vinyl, and it did not come loose at all after more than ten years. What a contrast!

However it's the round Yakima bars which I consider to be the #1 downside of Yakima's roof rack design. The square Thule bars meant my previous Thule rack with 2 or 3 bike carriers attached made a single solid and stable unit that was easy to handle when I lifted it on or off the car. Not so with round bars. No matter how firmly I attach the bike carriers, they pivot on the round bars. It's harder to focus on not scratching the car roof when I lift it into place because I also have to focus on keeping it from twisting and turning at each joint like some kind of giant geometric puzzle. This is true with either 2 or 3 bike carriers firmly attached (a Viper, a Copperhead and a King Cobra). I read round bars are even more of an issue if you get a canoe carrier, where the front and back canoe carriers are independent of each other and can pivot on the round bar as you try to load a kayak or canoe.

Put them all together, and I'm standing with my feet at the base of the open rear car door while lifting this bike rack over the top of my car trying to simultaneously: 1) watch to make sure the clear protective gel pad isn't falling off one of the feet, 2) keep the assembled rack from suddenly twisting and pivoting in my hands so one foot suddenly hits the roof, 3) watch to see if all 4 of the Q-clips are still spread the same (so most of the weight isn't pressing down on one clip when I put the rack down), all while I try to 4) put it down gently in the right position so it won't slide and scratch. It's a coordination challenge even on a good day. These things just weren't such a problem with my Thule rack.

Also the Yakima end caps seem to be made of a much softer plastic than the Thule end caps. Very very minor issue, but my end caps already look beat up like crap after just one summer of use, just from setting the rack down and picking it up again off the concrete on my garage floor or my driveway a dozen times or so.

Keep in mind that if you leave the roof rack on your car all the time, the round bars may not be an issue for you. Because I care about saving gas, carbon emissions etc, I put the roof rack on my car when I'm going to haul bikes then take it off again when I'm done. This was not a big deal when I used a Thule rack. My car (a Camry hybrid) averages 35-39 mpg unless it's really cold out. When I've left the rack on for a whole tank of gas such as long out-of-state trips, an empty bike rack takes about 4 mpg off my gas mileage (figure 10-15%) while a fully loaded rack with one-to-three bikes driving on the interstate at 65-75mph can take off a good 6-8 mpg (figure 20-25% at highway/interstate speeds - the faster you drive, the more drag cuts into your gas mileage). Before I bought my new rack I looked long and hard online at other posts on how it affects gas mileage, and these % seem pretty consistent with other people's cars.

I used a Thule rack system to carry bikes on my cars from 1994 til 2007. After 14 years the Thule cross bars had lots of cracks in the plastic so you could see the steel underneath. When I bought a new car in 2007 I decided it was time to get a new bike rack. Any roof rack (that isn't permanently/factory mounted) inevitably ends up scratching the finish on your car roof somewhat and I wanted to minimize this. I read lots of online reviews and went with Yakima this time, thinking it might fit my car better since more rounded roof designs on many newer cars means the front and back feet of the rack won't necessarily both be at 90° angles to the bike carriers. And the round Yakima bars do look a little sleeker. After just a few months using my new Yakima rack I really wish I bought another Thule rack. Instead of minimizing the scratches, I have as much scratches on my roof from the Yakima rack over the past summer as I got from my Thule rack in over a decade.

Tip for any roof rack from a long-time owner - use a clean damp towel to clean the pads and clean the places on your roof the pads will contact EVERY time you put the rack on your car. Any grit that gets in between the rack and roof will wear your finish. I'm still looking for some kind of clear plastic decal I can stick in the four appropriate spots on the roof of my car to protect it (I started looking when I first got the new rack and by now it's already a little late...)

If you plan to take the rack on and off your car frequently, also carefully consider the weight of each component you add. Some of the "better" and most expensive bike carriers are also the heaviest, so something like the Boa for a 3rd bike could make the rack a lot lighter and easier to handle. The bike carriers can vary from 4 or 5 lbs all the way up to 14 or 15 lbs each.

In general, the Yakima roof rack products seem to be good quality and well-built. I would be very happy with the Viper, Copperhead and King Cobra bike carriers if I put them on a Thule square bars and Thule towers. I had the Copperhead on my old Thule rack for years. To be fair, I think the new towers and carriers today are heavier than the old ones (whether you buy Thule or Yakima), plus my new Camry is a wider car than the Saturn SL2 or Toyota Corolla I had before. Both these things may contribute to added difficulties in gently and easily lifting the rack on and off the top of the car. However I do not think either the weight of the rack or the width of the car would be an issue by themselves if not for the fact that the Yakima rack always inevitably pivots and twists in my hands as I'm lifting it into place plus the protective pads that want to fall off. Keep in mind that I work out every morning (including over 40 pushups) and on occasion handle a shovel in the yard for 6-8 hours with hardly any breaks, so if you're not physically fit you'll be even more likely to scratch your car roof lifting the whole rack on and off as a single unit. There's a lot to be said for trunk racks if you don't have a lot of upper body strength and want to take the rack on and off your car a lot.

I was also very intrigued by the Atoc Draftmaster Sportflite. All the Draftmaster racks have the bikes in the same front-to-back position as a roof rack, which is better for mileage than standard trunk racks which surprisingly have more drag than a roof rack when the bikes face sideways to the wind. At the same time Draftmaster puts the bikes where they're easier to reach, so for someone who wanted easy access plus less of a mileage hit they seemed the best of both worlds. And unlike most Draftmaster racks, the Sportflite would not require me to spend a couple hundred to add a hitch on my sedan. However a roof rack had the major advantage that I can carry all sorts of other large items on my car roof attached with bungi cords. Some reviewers also mentioned the Sportflite's two supporting arms put enough weight on the trunks of sedans it can sometimes make two indentations. I asked a body shop whether they could add a reinforcing bar inside the trunk but they didn't know any way to do this without the heat from welding weakening surrounding metal. With hindsight, even if I did get a couple indentations in my trunk, they might not be any more noticeable than the scratches I get with the Yakima roof rack. In your case, one of the Draftmaster racks might be worth a good look.

Hope this helps you learn from my experience.

Solid tower system
These towers have a good, solid feel to them. Once you go through the initial setup, they are a snap to take on and off the vehicle. The entire system is simple and light enough that one person can assemble and place them on a car in minutes.

Be sure to place a good piece of fabric or some other protective lining between the base feet and your car, and be sure to wash the area as well before installation. If you choose not to, you will have permanent scratches. These Q Towers clamp very tightly to the vehicle, and any grit caught below them will grind down even the best paint.

Good rack
I bought these towers and rack components for a VW Passat sedan. One bit of advice, install the metal clips to the towers BEFORE you put the rack on the car. They take some elbow grease to get into the towers, and you inevitably end up shifting the rack position in the process and have to re-measure and position twice if you follow the Yakima directions as written.

Also, if you are planning on keeping the rack on your car full time, get the fairing. Trust me, the noise level without it is quite high.

Poor security
Yakima really blew it when designing the security of their new towers and accessories. The lock engages a thin tab on the glass-filled polymer cover. Once the cover is lifted, the cam releases the tension on the Q Clips and the entire rack can be lifted off of the roof. With the cover locked, there are several pry points that can be attacked with a flat-bladed screwdriver or pry bar. The fit of the cover is very loose and it can be lifted about an eighth of an inch. I can also pry the cover with my bare hands enough to fit an even larger lever behind it.

I owned a set of SST towers back in the mid-90s. The tensioning screw was pinned to the back of an all-metal lock body, and the lock engages the metal clip and also locks the tensioning lever. While the new Q Tower design allows greater adaptability to different roof lines and ease of attachment/removal without having to readjust the tension, once the plastic cover is compromised, say goodbye to your rack and everything on it. I used to leave my SST rack on my car when not hauling gear. That won't be the case with this rack.

The Thule 400xt tower seems similar in design to the old Yakima SST tower however, the lock body on the Thule seems to have a plastic cover as well. I don't know whether there is a solid metal cover underneath it. Also, it only fits their rectangular crossbars.