We've been Mount Snow season pass holders for several years now. I ski and my husband snowboards. We have seen several great snow years with skiing into April, and one not-so-great one (2010!). It can be insanely fun up there on weekdays, if you can get away. We stopped bothering to go at all on Saturdays because the lines were so long and we were afraid of running over little kids etc. I think the new 6-seater bubble chair should remedy the lines to some extent, but it won't make the slopes any less crowded!
We occasionally visit the terrain park, but are mostly looking for good snow on steep slopes and some glades here and there. At Mount Snow, you have to go the North Face for steep slopes, but since it is the north face, it can be icy. I wouldn't mind a few more black diamonds, but there is always Ripcord! There are some fun glades to discover on the north face and around Carinthia. We haven't been that excited about the mass conversion of slopes to terrain parks, but I think they have all the terrain park they are going to build at this point. Mount Snow is probably great for the advanced skier/snowboarder who is really into park stuff, but for advanced skier/snowboarders who aren't into parks it's not as good.
Mount Snow has a local feel and the staff have always been really friendly. The lifties will joke with you and the Mount Snow ambassadors are just there to stand around and be helpful. We love the free bag check. Since we are semi-local and trying to be cheap we always pack lunches and it is awesome to be able to just leave them at the base. The lodge can be crowded, but it's usually a friendly crowd. You are likely to meet a new friend while drying your socks by the fireplace! Final note: Parking's not bad either.