They just changed some stuff about them. They changed the $3CPM to 90/10. You will make more money off the 90/10. Also, I heard there isn't too much of a problem if you do want to leave.
Also, they used to be at least 5k subs, they changed to 1k a couple months ago.
I am a new channel, and I have spent probably over 50 hours looking into networks lately. I have gotten contacted by pretty much any network you can think of(Except large ones) but I think I'm going to wait until I reach 1000 subs and try and join UFG. Even if I start off with them, I could leave at anytime if I got really big, but I hear a lot of people don't leave once they join.
Don't quote my on any of this, this is just information I have gathered with my research.