As a gig venue, Brudenell Social Club is fairly obscure compared to the more well known Leeds venue, O2 Academy. However, attend a gig there and you will be pleasantly surprised.
The atmosphere here is very relaxed, and while watching the gig it is perfectly permissible to sit at the back and observe, or push to the front and enjoy the live music. There is an adjacent bar, and while it may feel like you are spending an evening at your local town hall, the venue soon livens up and you begin to forget where you are.
You won't see any major stars at Brudenell Social Club, but if indie, unsigned and undiscovered talent is your thing, then the gigs here will be right up your street. I attended a gig of a band called Swim Deep, which was introduced to me by a friend.
Tickets to these gigs aren't very expensive either. The only negative issue is the lack of security, which meant that a drunken fan was able to climb onto the stage during the gig and was not removed. However, this was the only safety issue and did not affect the night too much.