I went once, just before christmas, and it was ace. It was residents only, but they still pulled it off. They did start pretty minimal, but after a while picked it up and played harder.
It's a tiny club, in a backstreet, and pretty hard to find as well. It was quite empty when I turned up (near the start) but it filled right up until it was a mad, surging crowd, with people dancing all over the place.
Definitely a reccomendation, and easy to get home from, because it is right by the main street in town (las ramblas).