The range of posts so far pretty much hit the mark so I don't wish to repeat. However, from an equipment point of view
there exists in Canada a very small, no thanks to CBSA/replica firearm issues being the same for them as for airsoft, community of milsim paintball players using 43 cal guns. You've probably heard of these very realistic
, gas-powered (CO2 or HPA)
paintball guns retailed by RAP4/RAM. These things are pretty much the closest to airsoft in their form and function but with the added tactile feedback of ejected "shells" landing on the floor with a satisfyingly metallic ring, a small paint splat and perhaps a short but painful sting when hit, followed closely by a trip to the laundromat the next day for clean-up.
Otherwise, the need for a more tactical style of play (great for CQB scenarios) and limited ammo (realistic reloads), etc. when compared against the "mainstream" paintball forms such speedball or woodsball where noisy 200 round targets, err...paint hoppers stick up from the gun taking away somewhat from the realism means that with the right crowd, playing milsim/scenario paintball with these RAM/RAP4 guns can
be equally as fun as anything that hurls a 6mm plastic BB.
FYI: Here's just one (mine) example of the kind of custom loadout one can achieve with these guns:
Unfortunately, like I said earlier, CBSA enforcement of replica imports has had a dramatic stifling effect on the 43 cal community in Canada. Without a steady supply of these guns and more paintball operations supporting their use at the fields, it hasn't seen the interest amongst players who like milsim/tactical but are unaware of the 43 cal gun's existence.
Some field operators and their insurance companies say that because these things shoot @ 350 fps compared with the 250 fps limits for 68 cal paintball, that they are dangerous and should not be allowed. This is a popular misconception. Sure, at point blank range, it can hurt a bit more but if these folks knew anything about basic physics, they'd realise that 43 cal paintballs actually suffer a disadvantage in terms of "breakability" of the paintball down range due to the lighter mass of the paintball and it's more rapid loss of kinetic energy as it travels towards the target. Meaning, you're less likely to get a paint break on a distant target using 43 cal paint than you are using 68 cal paint (higher mass = more kinetic energy upon reaching the target), and that forces you to play "smarter" than the average Joe. I've been shot at point blank with both 68 cal and 43 cal paintballs and believe me, I much rather prefer getting hit with the 43...it stings more initially, but doesn't leave the massive bruises a 68 cal ball can.
As for the quality of the players, yes paintball has attracted younger more immature players to the game, but they just make better, more satisfying targets for the older guns. As in airsoft, you can find like-minded players in paintball to hang out with. There are a multitude of special interest groups in paintball catering to all kinds of players including milsim/tactical ones, though you will have to look a bit harder to find them, and whichever path you choose remember the ultimate goal is to have fun and be safe out there.