Prosperity Social Club is an ok bar with ok food with a generic atmosphere. The service ranges from ok and cheerful to slow and surly depending on which waiter you get. We had one of the owners as our waiter last visit an he knocked one of our party's hats off the table three times, stepped on the hat, then told us he should wear the hat if he didn't want it to get stepped on. He was extremely rude and unprofessional.
There are so many bars in Tremont that offer better service and atmosphere that I don't know why Prosperity seems so beloved. It's ok as a last option if every other bar is packed, but it would never be my first choice.