I like the long and skinny boxes, because they are easier to load, and they leave roof rack space for kayaks or bikes. They are also long enough for fishing poles or XC skis if you do any of that. The wider boxes tend to be shorter.Which model box?
If you are family with a quiver of skis for each member, you will need two of them, or one giant box.
BTW Watch out with big roofboxes or lots of other stuff on the rack, most cars only have a 165lbs roof load limit, which includes the rack and box itself. Yakima’s website will let you check the actual limit for your vehicle.
I love the roof box, because it keeps the snow out of your vehicle as well as sharp edges away from your trim. It’s also easier to load.
I line the bottom with a foam camping mat cut to fit (or you can buy an overpriced one from Yakima) and put some pieces of foam mat between pairs of skis to protect them.