We cover ours. Adco are good and kinda premium for the mid-price segment.
Since they all use a Tyvek type kind of material (that is best) that is the weak link for wear or tears.
Classic Accessories was good but they seem to have re-figured their Class A covers and now are only 135-140" for the side wall = too short for most newer premium models.
Expedition was a good brand last time we purchased...and sold affordably by third parties like Amazon.
I would just avoid the "Universal" types with no door or corner zippers. These are just a big bag with draw string (hard to install, hard to remove, hard to enter the RV when covered, and do not fit well).
I posted more about our covers here:
http://www.irv2.com/forums/f121/outl...ml#post1681530
Best luck