Delightful decision that you’re facing. I think that you and your daughter will be happy with any of the destinations you’ve listed. All are delightful places to ski, have very good ski schools, and enough non-skiing diversions to keep your daughter happy. From a skiing standpoint, all of these resorts offer their own charms; have a lot of mellow terrain, and sufficient challenge to keep you in a state of near constant glee for the duration of your stay.
Regarding your concern about ease of travel with Little Miss Sunshine, and taking into consideration the fact that Mrs. Bruno does not ski, I’d suggest Snowmass as the most suitable of the three. Snowmass has a very high percentage of slope side lodging, a MAJOR consideration when vacationing with a 5-year-old. After delivering the Little Princess to ski school, Ms. Bruno will then be free to hop on the bus to Aspen, and max out all of your credit cards. Parking in Aspen is a game best played by locals. I’ve not the time, temperament, nor inclination to deal with that type of hassle while on vacation, so would not usually consider renting a car there. The bus system is an effective means of transport, and if it’s late, and the little one is tired and her patience is waning, y’all can take a taxi back to your lodging.
Aspen nightlife can be anything you desire, but how much high living will you do when traveling with your daughter? Champagne and Cheerios while not mutually exclusive of each other, are not a traditional pairing. Not much going on at Snowmass at night. Family meal followed by story time has always worked just fine with us, but can’t say what will work for you.
I believe that the major consideration guiding your choice should be given to your wife, and what she wants from her winter vacation. How refined, sophisticated, rustic, culturally diverse, snooty, fancy, and etc. would she prefer her destination to be? (Note that “refined” and “culture” are terms that are relative to your expectations. If you’re from NYC, then the high culture of any of these towns may seem lacking. Then again, NYC snow is mostly grey slush, service professionals can at times be a bit surly, and the lift system stinks.)
Steamboat is a quaint mountain town. Unless she wants to rent a car for day-trips, then the rustic charm of the place is the whole deal. Genuinely friendly folk, a bit of solitude, time to read, hot springs, reasonably priced food and the like if you will. Not a whole lot going on in the base area at night, but there were enough restaurants within walking distance to offer several nights worth of variety. (A note though, we just had a winter sports show in town last weekend. I spoke with the Steamboat representative, and he informed me that the base area is undergoing major renovation. My favorite, quirky, affordable, ski-in, ski-out lodge, The Thunderhead is no longer open, and many of the restaurants and shops in Ski Times Square are to be demolished in order to make way for new construction.) Shuttle bus service between the mountain and town is convenient, reliable, and frequent.
Beaver Creek, (where I’ve never stayed, just skied there a few scattered days over the years,) seems to me more of a luxurious resort setting. Charming, expensive, and quiet. Ms. Bruno can get pampered at local spas, visit some shops, and relax. A car opens up a slew of day-trip options, and affords a wide array of dining, shopping, and people watching choices in Vail, Avon, and a surprising variety of options in nearby Edwards, where your daughter, if she’s a carnivore, may love Larkburger.
Some may scoff at the degree of challenge offered by Steamboat, but many of these naysayers don’t know where to look. Not gobs of major league steeps, but there are still a bunch of cliffs to huck, tight trees to negotiate, and long sustained-pitch bump runs, so unless you are a major free-ski film star, Steamboat should have a sufficient array of stuff that’s tough enough to keep you happy. Look for some lines that are not named on the trail map. The same goes for Beaver Creak, plus Vail is just a short drive away. Your BC lift ticket is also good at Vail so the variety of terrain available is tremendous. Snowmass is of course just one of the four areas that you’ll be able to access there, and if challenge is your main concern, just hop on the free shuttle bus and spend most of your ski days over at Aspen Highlands. The Cirque and Hanging Valley sections of Snowmass are plenty gnarly in their own right, so there are plenty of places to get yourself into trouble there. If high winds keep the upper lifts from operating, the bus ride to Ajax or Highlands is always available.
Cheers and have a great trip.