Off of Highway 5, just north of Magic Mountain (Parker Exit).
From a first-time player...
The place is open from 9am-4pm, and we played the entire way through (minus a quick lunch). They had several speedball fields, a city, an awesome woods-like field with trenches, and a field with a bunch of old truck tires for cover. All the fields were small-medium sized which helped push the action. I would say most games lasted between 5-10 minutes, so we got a lot of games in throughout the day.
The staff was super-friendly from the start. The refs kept good focus on the game, and had good control of the field. We had a lot of other first timers who were intially not listening to the refs, and were disregarding rules by taking their goggles off, shooting paint at one another between games, and even wiping. The staff handled the situation very quickly and professionally by explaining to everyone what rules were broken, and giving everyone another chance to quit acting up.
All the experienced players there were helpful, coaching the beginners on how to shoot, and some tactics. Although it was our first time, we did not feel unwelcome at all. There was a little tension between the regulars and the new problem players, mostly because of the cheating.
The rental equipment was good. They provide you with a good gun (mostly Tippmann 98 Customs), a mask, and paint holder for extra ammo. I think you can also get one-piece suits to wear over your clothes, but I did not use one. Very few problems with the equipment (no more than you'd expect for rental gear, considering how rough it must be handled day-in and day-out), and any problems with equipment were either fixed by the ref immediately, or they replaced it promptly - so that was great.
I didn't know they had food there, so I brought my own. They sell dogs and other similar types of food. A bunch of people went out to Carl's Jr, which is only a 5 minute drive - so you don't really have to bring your own food. It's nice to take a break in the middle of the day anyways. The games did not stop when we ate. If you wanted to, you could play straight through. I hear some places have a 30 min-1 hour lunch break.
I can't say how this compares to other fields, but my friends and I had a great time. Like I said, it was our first time, but we are totally hooked already. If this is considered a "good" field, I wouldn't be surprised. If it's considered a "bad" field, then I couldn't imagine how much fun I would have in a "good" field.