To get into Vain you will have to pay cover, which on most nights will also get you into Dixie Dance Hall (directly below Vain on the 2nd floor). This is an upscale Nightclub with a dress code at management's discretion, so don't expect to get in if you're wearing a t-shirt and sneakers.
Formally known as Black Cat Lounge, Vain has by far one of the best Sound & Light Systems for a Dance Club in all of Southeast Texas. If loud music is a turn off, then this is NOT the place for you. The dance floor is large with plenty of room if you're with a group of friends. There is also a VIP area with bottle service & Go-Go Dancers (some of them hoop and are actually really good). Personally, I've never had a problem with service/getting a drink from one of the two bars that are available.
Music is typically House/Top 40 Remixes. Sometimes they will bring in a guest DJ/artist. My only gripe is that I just wish they would play more of a variety of dance music. At times, I seem to be able to predict (with high accuracy) the next song/music selection. However, their resident DJ is definitely good at mixing, which is a plus. Also, I don't know of any other club/establishment in Southeast Texas open til 3AM on Friday/Saturdays.