Here are my thoughts on a few locations:

Hilton Cleveland South - Decent food and great staff who remember your name and always go out of their way to make you welcome. Though the hotel is just okay.
Hilton SLC Center - Really friendly and decent spread with a nice view.
HWV - Breakfast is a total beating here. Demand breakfast coupons when you arrive. My kids love the cookies and the munchies at night are okay, but the staff is pretty useless.
Hilton Amsterdam - When I was there in January, the staff were super friendly. The food was good and constantly being refilled and we always made a point of drinking and snacking before we went out every night. Probably my most positive lounge experience in a while.
Hilton London Kensington - Pretty crummy, just like the hotel. My wife lasted all of 5 minutes in there before she decided it was time to leave.
Hilton Washington Dulles - Typical breakfast fare and really average service.
Hilton LAX - A total mad house and the food was very average.
Hilton San Francisco - Great view but really average food.
Palmer House - Had a great time in this lounge. Everyone was really nice, it was really comfortable, and the food was pretty good.
The Drake - My favorite in the US. Great view, great staff, and even better it was open late. Me and a buddy still talk about the great time we had in the lounge watching tv and having the staff constantly asking us if we wanted anything else to eat or drink up until about 11pm.
Hilton Milwaukee City Center - Neat bar setup and free beer the day we were there. Food was okay but the hotel left a lot to be desired.
Hilton SNA - Great staff and pretty decent food.
Hilton MSP - Remember eating a real breakfast(scrambled egss and bacon) and an attentive staff even on a Saturday.