I used Butler Creeks for years and liked them well enough but always seemed to have issues with the pins sliding out of the cover. Broke a few over the years too so I was offered a new neoprene scope cover to try.
I used it last year quite a bit and actually like it much better than the BC caps. Pops off easily and slides right back on when your done shooting.
http://www.scopeshieldalaska.com/