Cargo? Yes definitely!
This roofbox from Yakima is the perfect piece of equipment for outdoor enthusiasts. Easy to mount, roomier than you could expect. The ingenious locking mechanism is easy and safe and numerous inside hooks allow you to attached your gear. Pretty useful when the box is half empty, which is pretty often because your car seats will be all occupied before the box says "no more". I didn't notice any increase in gas consumption at normal highway speed (55/75) and no additional wind noise.
The only downside: On a SUV, pay attention to the indoor garage clearance, because this cargo box increases a lot the height of your car.