Decent but Not Up To Hilton Standards
I am by no means an expert in Hilton Hotels. I have stayed at 3 in 3 different states. However, I do travel extensively and would consider myself somewhat experienced when it comes to hotels. The reasons I can't give the Millenium Hilton higher marks are as follows:
Front Desk Staff: This was the one highlight I had. The staff at the front desk and the supporting staff were great. Very friendly and they had my requests on record and happily fulfilled them.
Pool and Gym: a rare find in this city, the pool and gym are great by all standards. If this is important then you can't go with this hotel.
Rooms: The room was clean but felt "dark". You can't expect any hotel to have rooms of any great size so I wouldn't take points off for that.
Concierge Lounge: as a frequent traveler, I depend greatly on the concierge lounge. This hotel doesn't have one! To me this is a huge deal breaker.
Restaurants: The restaurant was good. The staff is very friendly and helpful. However, the "bar" is right by the elevators. I was traveling with my family and I didn't really care for the atmosphere for my kids.
Location: Great. I can't say much about that. 
Overall: If I was traveling alone I may have given it an extra point but I was with my family. I did not want to stay there with my kids. Hilton hotels and staff are great but the layout of the entrance didn't make it very kid friendly. There is nothing I enjoy more than to relax in the concierge lounge of a hotel after a long day of work but this hotel doesn't have one. It is truly a shame.