I didn't really like the 'boat, I thought American Ski Corp needed to pump more money into their mountain. Granted, last year they did get a better park crew and things improved a lot. I guess I just like the option of going to 7 mnountains.
Steamboat was some of the best snow I've ever skied though, it's a hard decision. I would say you need to ski steamboat at least one year of your life, it's that good.
Steamboat ( little on the short side but long pipe {great for learning}, just added some really nice boxes, nice rail runs, small/medium jumps, accessable back country terrain is a huge plus, large snowfall, lower elevation (snow melts quicker), huge drops with forgiving landings.)
breck (extremely nice terrain park, mini pipe, big pipe, small jumps, rail run, and they just opened the big boys {45ft, 60ft, 60ft step up}, keystone (night skiing, sweet jibs, and awesome jumps this year), vail (big mountain, nice jumps, really nice half pipe, drops & cliffs, sick trees, and quality rails), a basin (latest mountain open, providing a longer season). There is quite a bit more going on in the towns (comps, concerts, people).