If approaching from Route 20 or Allen Road turn south on Brier Hill Road by Allen's Corner (a restaurant and autoshop with junkyard in back, it's hard to miss), go over the railroad tracks and it'll be shortly on the right marked by a concrete block. It may be difficult to pick out but it'll be the dirt road next to the tracks. If approaching by Route 72 turn north on Brier Hill Road and keep going until you see the concrete block on your left marking the dirt road just before the railroad tracks.
Operation Paintball is an excellent field of people of all skill levels thanks to it being a versatile field with a good staff and is an all around fun place to play at.
To start off with safety, this is a place where a parent could bring a five year old and still feel safe. Granted, I believe the minimum age is twelve or something so you won't see five year olds there, but the point is that they take safety seriously there. They chrono every gun before you can play with it, including their own rentals. Blind fire is not allowed. The refs are very attentive and keep a good eye on what goes on in the matches and there's sometimes two refs watching a single match. Overall it's a very safe course to play on.
There's several fields to choose from that offer something for players of all kind. There's a couple of small woods courses that offer a good point in between traditional woodsball with some of the element of speed found in speedball. There's also a large woodsball course called Mother that has a small fort where they often have one team defending and a second team attacking it. They also have an airball course that they frequently change and many of the refs take pride in setting up the best airball layouts that they can.
There's also a series of small static speeball courses. One involves small wooden walls to take cover behind that radiate out from a central point. While I've only played team elimination on it it appears as though it's built for a king of the hill or a capture the flag match. There's also a course called Panic which is the smallest of the courses and consists of barrels as cover on this tiny course. Matches on Panic are usually very quick and the ten foot surrender frequently comes into play given the size.
And then there's my favorite, Trenches, which is just as the name sounds. It consists of two trenches on each side linked by short perpendicular trenches. I'd estimate they're about five feet deep, which gives most players good cover with only their heads sticking out when standing up. This allows most players to easily duck down for excellent cover and pop up to shoot. In between each side is a no mans land with a small mound and a pair of small wooden walls to take cover behind when trying to brave no man's land. The only problem with this course is that the last time I had played it the course was severely overgrown with vegetation which made it nearly impossible to see out of your own trench. While this made for a very fun match crawling across to sneak to the other side it defeated the idea of trench warfare. However when they do keep it trimmed up a bit it's a great course to play.
The facilities aren't anything fancy, but they fit the field environment and are more than adequete. A couple of porta-potties for relieving yourself and then a roof over the table area next to the trailer give you all the comforts you need. They also sell refreshments from the trailer in addition to paint, pods, and other rental gear.
As I've mentioned before, the refs at Operation Paintball take their job seriously and do a good job at it. And while they're very professional they also try to make it a fun experience. They're very polite, very helpful, and they always keep safety in mind.
I've also never had any sort of problem with any other players. All the regulars at the course are very polite and are just as willing to help you out as if they work there. The regulars take pride in the field and are there to have fun just like everyone else.
Overall I highly recommend visiting Operation Paintball if you're in the Chicago or Rockford area.