For us... it's like a guaranteed game day pretty much. Rain and most weather, unless extreme hazardous driving conditions get in the way ( or work of something silly like that ) ... Sogo's being indoors we get that play day in every month.
Plus, we get to meet all sorts of players. From Experienced sneaky big players like Joe ( who has managed to sneak up on me twice!!! ) , to the guys that dressed all SWAT team like, and Tang who compared cars with Cody out in the parking lot... and busy guys that sometimes ref and shoot at each other while reffing... to the new guys that hadn't ever played before.
Plus, Jon is always full of advice and has neat ideas, and seems to always give ya insight onto the other side of things you don't think about. That is, if you can get him still for a minute, lol!
I've only been twice... both times had more than 15 players all day, I think the first time, we had close to 30 if I recall correctly. ( Man it was hot too! )
It's fun. Really intense. It's a bit different than outdoors play , almost like comparing apples and oranges ... almost. Everything is at a faster pace too.
Meeting the other players is probably a big thing to us too. I know from experience that many teams will not play with others they aren't at least semi-familiar with, so meet and greets ... then shooting at those you just made acquaintances of, goes a long ways for future endeavors.