We also have the 2100 and store outside since purchase in 2012, but last two years under a car port. We have always covered. Some cons we were given when investigating covers are:
1. Makes access more difficult -- We have not found this to be a problem. The covers all have zippers and if correctly positioned work fine.
2. Will rub on the finish -- We get some very serious wind and have never seen a problem. Just did a serious exterior wash today and saw no signs of rubbing or damage from the cover. Inside of the covers is soft and if nip/tucked properly not much slack to flip and flop in the wind.
3. Very expensive to get a custom cover that fits perfect -- Yes, the PCs are unique sizes which makes it more difficult. Our first cover (2 winters) was a 24 ft. motorhome cover and we did some creative nipping and tucking with extra ties. The biggest problem was the height from roof to ground. Cover was way too long, drug on the ground and was even frozen in snow melt (stored at 9,200 ft. in the Rockies) when we wanted to pull it out in April. We now use a cover for a 22 ft. travel trailer purchased from Camping World when on sale. Height and length are perfect. We add a couple extra ties across the windshield to nip/tuck the extra and works fine.
I believe our exterior and roof are in great shape thanks to keeping it covered in the winter. Because of the serious sun at altitude, if we were home for more than a few weeks prior to the carport construction, we put the cover on. Have developed (through trial and error) a slick system and the cover goes on and comes off fairly quickly.
Let me know if you have more questions. Nicki8