I been looking for a few years in NYC and I have done extensive research. I can tell you that there is nothing TOP quality here. The best way is to get together with similarily minded people and train amongst yourselves.
I tried getting together a few people from Sherdog to form a group. Initially, people showed interest but when I got the place together and sent the people a private message, I got no response.
So, I'll post it again here. As far as the space is concerned, the fighthouse on 27th street charges $12 per person to train there for two hours. They have a ring and mats. If anyone is interested, please post what times are good for you. For me, any weekdays after 6PM work for me. However, I cannot stay at the place past 8PM because I get up early the next day for work.