Jake-AudiUSAParts

I have an absurd amount of experience with roof racks and over these many years I have only ever used Yakima products on my personal cars. I have installed and dealt with both brands extensively so my knowledge and opinions are based on experience with both brands. Most Yakima accessories (bike attachments, ski attachments and so on) have adaptable mounting clips that will fit the rectangle bars of the Thule systems, making them semi universal. The newer "aero" type bars from Thule and Yakima utilize a T-Groove that is compatible with both brands as well. I have never liked the Thule rack parts as they feel cheap to me and I have dealt with many more returns of Thule products than Yakima over the years. As for the roof top boxes, Thule makes fantastic boxes along With Yakima, so as roof top boxes go you can't go wrong with either. One thing I never understood was the rectangle shaped cross bars of the Thule system, I am pretty sure a circle is stronger than a square and if you see a beat up old car with a beat up old Thule rack on its roof the bars are almost always sagging in the middle. Just my 2 cents....

QShip

With regard to wind noise with the roof open. The Whispbars are fairly quiet up to about 55+ mph in my experience.

Jacket

Thanks for the feedback on the wind noise. The round Yakima bars on our old MDX sat right above the sunroof and made a lot of noise - the sunroof was all but unusable, and we tend to leave the crossbars installed year around. Mounting the cross bars as far back on the roof as possible is one way to reduce the noise.

Compatible in what sense? I'm thinking of accessories like my Yakima fork mount bike trays that use a round "clamp" for the front mount that fits flush with the round bars.

I know the roof top box I have will work with the Aero bars, but I'm doubting the bike carriers will.

Jake-AudiUSAParts

Sorry, I was not very clear in my statement. If you have “T groove” rack accessories like bike racks and boat, hull holders that are set up for the aero style T groove bars they will work on both systems as long as they are both T-groove systems. If you have traditional, rectangle Thule bars the newer Yakima rack parts come with mounting clips that will work on both bar types, If you have older stuff you can still go to a store that sells rack systems and purchase new, “universal” mounting clips for a few bucks. We are lucky out here in Portland as we have a place called RE-rack that buys and sell rack parts and has a massive selection of clips and adapters. I hope I have cleared things up a little, I tend to ramble at times 

Jacket

Makes sense - thanks. The only Thule stuff I have left is our Atlantis 1800 (nice box...); everything else is Yakima for the round bars. I'm leaning more and more toward the Aero cross bars for the wind noise reduction, and using our hitch mount carrier for bikes when needed. If we ever get another camper to tow I'll have to mount bikes on it.