Have a Thule Frontier with an idiot-proof single locking mechanism; can’t pull the key out unless it’s closed. It’s a little bit larger than the Summit, but not as huge as the Mountaineer. With the Frontier on my roof, I still have room on my bars for my two bike trays. Since it’s never off-season in Colorado, I wanted a pod that was not aerodynamic (I drive a Grand Cherokee which is one of the most un-aerodynamic vehicles created), not lower in profile, or not ski specific. In the summer, I can creatively fit three to four fully stuffed 6000 cu.in. packs in the pod. Also, it’s a great place to stow your nasty smelly gear for the ride home.
Disadvantage: I can’t fit into my garage at home and some parking garages. Also, depending on your load, it may/will make your vehicle top heavy. I’ve had to un-weight my pod a couple of times on some side slopes while 4-wheeling in the backcountry.