I used to play about 10 years ago, back in my hometown. I liked it, but the times they'd go out to play conflicted with my Saturday morning work schedule (thanks Dad!
I still own a Brass Eagle Pirahna with a Semi-auto trigger (its a pump action, but hold the trigger and it'll auto fire on each recocking), and then a custom Spyder with ported barrel, expansion chamber, venturi crossfire bolt, and custom paint by yours truly.
I'm finalizing purchase of a true firearm, so I may pull out the spyder and get back into paintball in the spring. There's an outfit less than a half mile from me.
Never played indoors though. Always outside, usually on riverside land with lots of bushes and trees, but it was cattle area too so it wasn't horribly overgrown either.