I have been going to Circa since it's opening last year. SInce Day 1 I have been in love with this place. So many fun things to do and see. Lots of room to see the action (my favorite is the second floor balcony).
Granted, I do not go to clubs on their regular nights so my view of Circa is only from the special events that I go to there (including Victor Calderone, Carl Cox, Pablo Ceballos, etc). On these nights, this place is on fire.
The crowd sometimes is full of people that enjoy their booze but I don't let that bother me too much. Enjoying the music and decor is what I like to do at Circa.
The Ballroom is another bar within the whole Crica complex and it's where a great vibe can be found when it's a special house music event in there.
When you go there, make sure to explore all the rooms including the bathroom on the first floor where you can find a full bar and DJ inside the bathroom. Also explore all the art instalations which change periodically so there is always something fun to see.