Overall: We found a lot of things to like about Four Seasons Vail, but there were too many small issues for this to be a 5 star rating. It appeared to us that the long term staff were very much up to expectations but some of the 'seasonal' staff did not know their job / enough about Vail to provide the standard of service we have found elsewhere.
Location: Vail is not a big place, but the Four Seasons is on the outskirts. It does take a bit to walk to the town centre or slopes. There is a free local bus service right outside to Vail centre and Lionshead every 8 minutes...as well as a shuttle from the hotel to near the gondola.
Room: We stayed for 12 nights and were upgraded to a suite. We loved the walk in wardrobe, huge bath, extra toilet, ski kit cupboard, refrigerator for our own drinks and, of course, the most wonderful bed.
Facilities: We did like the outdoor pool (with heated towels / robes), jacuzzi's and large indoor spa. In particular soaking in the hot spas after skiing was a great way to be ready for the next day. The ski concierge is within 100 yards of the gondola and is a real wow factor.
Service: Highly variable. To pick out contrasting examples - the bar manager went out of his way to buy a scrabble game for us, the concierge team gave advice that was insightful and proved some tripadvisor ratings wrong and the ski concierge team always had us off skiing quickly and in warm kit; alternatively - drink orders forgotten, do not disturb signs ignored, spa appointments incorrectly confirmed, room not cleaned when asked. It's hard to be great at service and this hotel does it much of the time...which makes the failures stand out all the more..
Value: Given our upgrade to a suite we have to say great value. We also found Vail to be much better value than the equivalent European resorts / hotels. The flight is worth it if you are staying for more than 10 days.
Restaurant: Flame is fine for breakfast (particularly with the buffet - a la carte can be rather expensive and slower than ideal for skiing days). We had Xmas dinner here and it was decent...but for a FS hotel I would expect something a little more 'wow'.
Bar: Liked the team, layout and drinks menu. Food menu was highly limited. Did not like the bard being shut until 3 pm...if you come off the slopes needing food and drink before then it was strange to find it shut. Likewise the coffee shop was shut for our first week...why?
Us: This is our sixth stay at a Four Season's Hotel and the second resort (Carmelo, Uruguay being the other).