Alta is definitely all about the skiing. On powder days, it can't be beat. Much of the mountain is ungroomed, so be prepared for powder and/or bumps depending on snow conditions. One of the great things about Alta is that it offers a variety of terrain, from wide bowls to tree skiing and, from the Supreme lift, rocks and chutes. If you aren't used to skiing powder and ungroomed terrain, I would recommend the afternoon clinics -- you can even take a black diamond-level powder clinic if you are at the expert level and want to improve your abilities in the deep stuff.
On powder days, various sections open up after avalanche blasting, which can mean that the lifts open later than usual, but there are ample opportunities for maing fresh tracks as long as you pay attention and get to the newly opened areas quickly. Some of the best runs are those below the High Traverse (turn sharp right at top of Collins Lift), the backside into East Greely (straight and to the left of Collins), and, when it's open, the Castles (but they require hiking).
It is true that Apres Ski is a little limited, but the food at the lodges such as Goldminer's and the Peruvian is good. The Goldminer's bar serves only wine and beer, but the bars at Peruvian and Rustler lodges have hard liquor as well. The atmosphere is more "rustic" and ski-centered than some other resorts (such as Park City), but the superior skiing, lack of crowds, and no snowboards policy are well worth it!