For my junior prom last year, my boyfriend and I went to Men's Wearhouse for his tux. Now, granted my dress was an unusual color, but the selection of colors for vests were limited at best. The qualtiy of the suit and the selection of suits available were wonderful, but the price was not. It was almost $150 for the tux for one day, and that was one of their more basic tuxes. The staff was helpful and knowledgle, though, and apologetic when we couldn't match the vest. As well, they gave my boyfriend referal cards to give to his friends that would give him a discount, but they didnt help much. If you've got the money to burn, go for it.
Pros: An amazing suit.