I've been a Fill A Seat customer across 3 cities for the last 3 years. I'm a big fan, if your new to the city many of the tickets it offers are in city centers or points of interest and having a reason to go is a great way to explore. If you've lived in your city for awhile you'll see many of the tickets are in familar places to shows you'd otherwise pay a lot more for.
This is a great service to explore, get value, take dates, and get out without having to spend or figure out too much.