This was our second time staying at Hotel Park City with our 3 boys, 8,6, and 3. Overall, it has most everything that a family could want on a ski trip...spacious rooms, great breakfast, outdoor pool/hot tub, etc. We especially loved having the ski rental downstairs, which was uber convenient. The staff was helpful, although when we asked about getting some drinks delivered to the pool outside they were clearly not set up for that.
The location is in between all of the mountains, which inspired us to ski at all of them. The downside about the location is that nothing is walkable. Yes, there are shuttles to a couple of the mountains, but we found that transportation was always an issue, especially with younger kids.
Overall, it's a beautiful, well managed place, but if convenience is paramount it his may not be your place.