I was just there for a conference and had my first stay at Bellagio. I can honestly say it was the best hotel I've ever stayed in.
The service was excellent, they were not pompous at all. If there was one disappointing area, it was the buffet. It was overpriced and not that good. I'd highly recommend their Olives restaurant. 4 of us ate dinner, appetizers and drinks for $120. Not bad for a fancy hotel. You can't go wrong with the Bellagio.