Which car top storage system is best? Thule, Yakima, etc?

We are planning a trip to the Happiest Place on Earth and typically just borrow our friend's storage rack. However, this time they will be using it the same week that we would like to borrow it. So, we are in the market for purchasing one. I guess, my question is: is it all about price? Is there a difference is the quality between brands? Any pros or cons to a specific brand? Any info (i.e. personal experiences) would be helpful.