We have paddled with other people with the Q Towers on different car models without a problem, so I think this is an issue specifically with the Honda Fit.
Now to actually review the product. We did alot of driving last year, carry 2 kayaks (over 4000kms) and we didn't have a hitch. The loud humming of the wind passing over the bars is annoying, but it can be taken care of with the "Windjammer" that yakima makes. They can be a pain to set up (It took 3 hrs for a professional installer to get mine set up properly) But when in place they are pretty solid. The plastic tabs for clamping the rack to the roof are poorly designed tho, and 2 of mine broke this year. You have to be very careful when clamping then down not to torque it too hard and press evenly over the surface or you could do like I did and snap them. In my opinion something like that should be made a little stronger.
I have no experience with Thule Racks, but overall I find this pretty good and would recommend them for any vehicle other than the 2002 Chev Malibu.
Whatever you do GET THE LOCKS! Not only do they keep vandals from taking the towers, but more importantly they keep the tension-keeping cover from coming loose!
Yakima customer service is great... really if you had that big of a problem they will help you. I am happy with my Q-towers and I recommend them.
Not a good combination. The Q-Tower rack system is actually very good, solid and easy to put on and take off.
The Glide N Set kayak racks are another matter. Mostly plastic, cannot be tightened enough to stay put on the bars. The tie-downs are extremely time-consuming to tie the kayaks down.
I needed the Q-Tower system for my racks due to the vehicle I use (F-150 SuperCrew). I should have insisted on Yakima kayak holders even though the Thule's are supposed to work on the round bars.