Paintball is way better, it puts hair on your neckbeard... Airsoft is for girls. 
There's a reason why law enforcement generally choose to train with paintball guns over airsoft. It's a much more engaging experience, it might be hard to comprehend, but when you are hiding behind cover like a tree and paintballs are smacking into the tree ripping chunks of bark off it will get your adrenaline going much more than if someone was shooting piddly airsoft bb's.
Ohyeah, and if you play paintball... Play woodsball or military sim... speedball is lame and arenas generally make u turn your guns down to ridiculously low feet per second (because they are always concerned about liability).
we dont use paintballs, well maybe some other departments do, but we used training pistols(glock 22's with a firing pin and Simunition rounds, or powder rounds), this gives the same effect as firing the live ammunition, because it is essentially live ammunition. The tip fires out a plastic cap filled with colored powder from a shell casing that is exactly the same as live ammunition with gunpowder. And it downright absolutely stings like a bitch, however force on force training is not used too often due to its expense and liability. These firing pins and simunution rounds can also be purchased for a variety of other weapons like rifles which then take your simulation to the next level. It truly doesnt get any more real than this, as this is a live gun with live ammunition, that goes bang loudly and has recoil.
When i turned 16 i had bought this below, it was my third paintball gun and i wanted to start getting into simulation paintballing, however i noticed that the guns could never really take you to that point, because unfortunately, paintball guns just have a hard time looking the part. Even this still had the silly hopper sticking out the top, the abnormally large barrel, the tank sticking out the back, and you couldnt use the sights with a mask on, as it was too bulky to get your cheek down.
Not particularly mine, but close enough to it, without the scope.
btw its an Ariakon Sim-15, which back then this was one of the few companies making these sort of pbguns.
Paintball is indeed fun and if my main goal was to have fun I'd probably stick to it, though it's generally much more expensive and the logistics are pain in the ass.
Since when airsoft guns generally use any sort of gas at all, you mean those 2% of replicas in use that are gas-powered? BTW. I have yet to encounter asg assault rifle powered with co2 (other than RAM), they all are greengas powered. So when you want to bash asg, do some research first. 
He is talking about the pistols mostly, they use these small cartridges, and some smaller rifles use these as welll, though they give you a very minimal amount of shots, like around 50 and your done. Then your spending your time attempting to grab a freezing cold metal object while putting in a new one.
Bonus video for why even the strongest neckbeard should be wearing head to toe cover, this is gas operated at its finest.
