I am going to purchase racks for my truck to carry my boats. One rack on the roof, and a rack that attaches to the 2" receiver for the hitch. It is a toss up between Yakima and Thule. I want to use a roller at the back, and a cradle at the front. Any opinions on either one? Square vs Round bars? I have Whisper Bars on the car with Bow Downs by Yakima, and they can be used on either aero, round or square. My preference is the Yakima for the receiver because of design, but it uses a round bar which apparently can be an issue with racks rolling over when loading.