Pros: Wide variety of terrain, state of the art lift service, non-existent lift lines
Cons: difficult to get to, lift ticket prices, private instruction prices
I should start by saying that I am not an employee of the ski company and do not live locally but have been skiing at this area all my life. I live near Denver and have skied all of the local front range areas as well as Steamboat.
In my opinion Snowmass is hands down the best ski area in Colorado for a number of reasons. There is a ton of on mountain lodging from stuff that is older (think '70's style low ceiling stuff) to brand new (ie the Viceroy) and therefore there is a very large price range. What isn't cheap and hard to get around is the lift ticket prices.
Here's the thing, the remote location, the absolute latest and greatest lifts, and the expensive lift tickets with little co-resort deals offered create pretty much no lift lines ever. The exceptions would be during the 2nd week of the holiday break (from x-mas to New Years), President's week in Feb, and maybe one week in March (3rd or 4th week.) So you combine the lifts with the enormous amount of widely varied terrain and you have ideal conditions for lift served skiing.
An update to another review on here, until recently there was a bit of an issue traversing from one side of the mountain to the other as the area is huge and you could think of it as a large "W" so getting from the bottom of one of the sides of the "W" to the other could take some time. Add the Sheer Bliss lift. The Sheer Bliss lift put in a couple of years ago vastly changed how you can ski this mountain. First of all it serves the ever popular Big Burn area which is by far the most favorite blue cruising under bluebird for visitors. The addition of this lift doubles the capacity to the top of the Burn to address the sometimes 5-10 minute wait times at the Big Burn chair during those peak weeks. The other thing the Sheer Bliss chair does is it runs up the middle of a big blue run which has single black bumpy runs into Garrett Gulch on one side and offers several double black options from Gowdy's and KT gully down the other side into the Cirque area. So you have a blue cruiser (or the whole Burn) and a big single black gully and some really nice steeps served and they all meet back at the same chair. Pretty ideal for me and my family as I have one child and my wife who are in that blue / black range, and my son and I who ski more the black / double black terrain and we all meet back up at the chair. I know, a long review of just one area of Snowmass but that chair literally has changed the face of the mountain. It also allows the traverse from one side of the mountain to be much easier essentially eliminating the need to ski down lower and ride two chairs to get back up.
Ok that is just one chair on a huge mountain but generally there is so much great blue to double black terrain on Snowmass it easily provides a week of entertainment. I would also mention that the glading that they do is extremely well thought out and there are very few runs with weird side pitches. Also, if you like groomers, you will find among the best here. The Aspen Ski Company leases state of the art grooming equipment and when they are done with it places like Winter Park and Steamboat pick it up but really the direct fall lines are what make these groomers great.
If you can't find enough steeps at Snowmass you probably don't know where to look. Gowdy's is one of the steepest chutes in the State, and all of the glades down into the hanging valley... well you could spend days exploring new lines in here. That said, head on over to Aspen Highlands and hike the bowl or ski Olympic bowl... it's on the same lift ticket and is a short and free bus ride away.
I could go on but if you're still reading this good for you, and you probably are ready to move on.