I've only played at Randolph, and it seemed to be mainly people renting, usually about 20 people total. It was 40 dollars to play there have free air and BYOP.
At fox4 we have huge 50 person games every day in recball and an excellent airball field. In addition, its 25 bucks to BYOP and play, or if you buy a 10 time pass for 100 dollars, its 10 times a pop.
Quite simply, i believe Fox4 is the best field i will ever play at. Cheap prices, great refs, great people. The games are huge and fun, and you can always get the kind of game you want. As a bonus, they have a fully stocked pro shop that has paint prices that are competive with online prices. I've been to fox4 easily 8 times, and i plan on going as often as i can until i move out. If you're getting bored of your home field or are just starting out, Fox4 is definitely the place to go.