what you should do is go to a shop and try them on. with that said, i wear an 8.5 shoe and have 25.5 1080's but should have gotten a 25.0. with an 11.5 you're looking at a 28.5 boot give or take a size because everyone likes a different fit. you should really go to a shop to be sure.
my level of radness... it just can't... be quantified.
Getting a 25.0 really wouldn't have made a difference for you. It's the same shell, actually, its even the same liner, generally they just change the footbed to make the liner a little more snug. These are reasons why you need to see a good bootfitter. So many little things add up.
is it really that hard to go in to a ski shop, and get them to size your foot and recommend something? i mean, boots are so fucking important in skiing, wouldn't you rather have something thats perfectly comfortable, rather than guess and hope its a decent size?
really not. The pro model really is the "course" boot, but softer and with the absorb cushion, where as the 1080 really is a crappy x-wave 6 ( low end model) with the same cushion... 2 tottaly different boots, made for 2 totally different types of skier..