love my Yakima!
I have a Yakima hitch mount rack.
Things I like:
The rack folds down when we aren't using it.
The rack will swing away from the vehicle with the bikes on it.
Things I don't like:
Even though the rack is made for four bikes, we have a hard time getting four bikes on the rack.
Even though the rack swings away from the vehicle, it is still a pain to have to do that when you just want to quickly grab something out of the back of the van. This would obviously not be an issue with a roof mounted rack.
hope this helps!