Cant speak too specifically to Deer Valley but have been to Park City 5 of the last 6 years (went to Breck last year). We usually carve out a day for DV and its fucking sweet. As I understand it, they limit the # of lift tickets, so it has an exclusive feel. Plus no snowboarding, so it automatically weeds out a lot of people. There are 4-5 top resorts on property (Montage et al level quality). While we have not stayed on DV proper, we have ventured to the Montage and you cant really go wrong with any of them. They have a great bar and lobby.
We typically stay near the Town Lift in PC so we can ski in ski out... several of the hotels on DV mountain afford the same convenience, ski valet, etc. Our friends rented a house in DV on the loop that leads to the mountain and with one call, they send a suburban to pick you up , very nice perk. They are basically on call for you to and from mountain, Park City, grocery etc... The ski schools are top notch, very good with kids according to our friends. I may be off here, but if Park City is like skiing a country club, DV felt like the Masters. IMO its several cuts above PC.
One of things that has drawn us to this area is the proximity to SLC airport. You really dont need a car to ski this area. 45 minute uber if you choose to not rent a car.