On Anon is just by Piccadilly circus and at first look it appears to be an excellent bar, many different levels, each with its own distinctive decor and style. I was in the Lodge Bar on the top floor for a while which is really cool It's done out like a mountain lodge with moose heads and bear skins on the walls and windows that over look picadilly circus. The drinks are pricey, but pretty much what you would expect from a trendy central London bar. Up until about 8pm on the Firday night I was in there it was really good, then came the crowds. They pack them in, it's very hard to get your own space, and going to the bar later in the evening was a mission in itself. There's also a club section that played cheesy pop and chart R 'n B which opened later on and unbelievably that was more packed than the bars, wall to wall people dancing on top of one another.
Alot of the clientele were stereotypical city types and I had the misfortune of over hearing one have an argument with a barman and come out with the cliched "I earn more in week than you do in a year etc etc". For novelty it's not bad, but if you want a proper night out with real people then I'd recommend you steer clear. Happy drinking.