Worked well for me.
I have only used it once, but thus far I am satisfied. Managed to fit sleeping bags and pads for three, two camping chairs, plus a couple of personal bags and some small odds and ends. Sturdy construction (once closed and locked). No major effect on gas mileage. Relatively quiet (notable noise, but can still have a normal conversation in side). Note: If you're a jump right in without the instructions kind of person, remember that you can only open one side at a time. I recommend this box!
Easy To Install
The 3D Maxpider Foldable Roof Bag was as advertised. It was very easy to install on our Yukon XL, and kept our bags dry through a rainstorm on the way home. It appears where the zippers come together is a factor in keeping the contents dry. It's sleek design did not affect the vehicle's gas mileage.