I kind of want to like Spirit, but when I think about going to events there, I just think about long lines and standing outside waiting. I guess it's pretty hipster to not really put effort into the venue.
I've only been to a couple events upstairs so I have no idea what the downstairs is like, but they typically only have one person doing tickets and checking IDs, and then had someone just doing wristbands. It would be better to split things up some so that the line can move faster. The bar upstairs was decently fast and they do take cash and cards up there.
I wouldn't go specifically to Spirit unless there was something I wanted to see that happened to choose Spirit as a venue. It's not terrible, but it's just not great either.