I use Barrecrafters rack to carry 1 board and 2 pairs of skis.
Thought about getting the box for the versatility and added "junk schlepping" capacity, but decided in the favor of the rack since it's a lot easier to mount and dismount. I do not keep the racks on the entire season, but only install them for the weekends - only takes 10 minutes.
Both boxes and racks will reduce your mpg. And since T4R is a daily driver, I keep on putting the rack on and off.
Thule and Yakima seem to be more expensive brands than Barrecrafters.
Check the eBay listings, you may get a great deal there on any brand.
Good luck.