Here is some Interesting info. I personally have tried the Yakima round bars for 6 years. On my new car I went with the whispbars because 1. they are quieter and 2. they sit much lower to to the car and look better. Sound of the bars is important to me, since I think the round bars are loud. I also use a cargo box so roof clearance isn't a big issue for me. But if you plan on using a ski rack and need to haul snowboards upside down then you might want to thing of roof clearance.
Btw stock Subaru racks are made my Yakima.