As a counter point to Eclectic Dreck, airsoft does indeed proudly sport the warfare simulation badge and I wouldnt have it any other way.
Having played both paintball and airsoft I can definitely assure you that paintball does indeed hurt much more. The mass of a paintball can deliver over 1.7 Joules of energy on impact while an airsoft BB can only deliver proximately .3 Joules (Both of these are off of guns that actually fire as safe FPS rates). People mainly think an airsoft gun hurts more (From my experience) because someone has walked up and shot them at point blank range. While this does hurt and makes you bleed from an airsoft gun, it hurts much worse to be shot from 6 inches away with a paintball gun (and is dangerous).
Also another plus of airsoft is the fact that you do not have to wear a full bulky face mask to protect you. Simple ANSI87 certified goggles or safety glasses do the trick. I play all my game using yellow tinted safely glasses and never had a problem. Sure getting hit in the face stings for a bit, but there is not any real danger for damage to things like your teeth and jaw like there is in paintball (again simply not enough mass in a .25 gram BB). Not having that huge face mask really lets you see and hear much better, which is crucial in a game where everyone is wearing camo from head to toe.
Paintball is also more expensive (ALOT MORE). A basic $150 paintball gun is something like a Tippman 98, semi-automatic, shoots decently straight, has a 200 round hopper. A good durable starting gun. For $120 dollars, an airsoft player can get an Echo 1, 1:1 scale M4 with a collapsable stock, that shoots 350 FPS fully automatic at around 8-9 rounds per second, that comes with a 400 round high cap magazine and a battery and charger.
2000 Paintball rounds will run you $60 for the crappiest kind.
5000 .2 gram BBs of good quality can be bought at Dick's Sporting Goods for $10
Airsoft guns do not cut balls and foul the barrel, the BBs do not get cut by any simple thing in their path, the BBs can punch through cover like a bush if you focus fire on the same spot and actually cut through, you can easily hold 6 or so more high cap magazines with a tactical vest without having those huge belts of tubes.
Actually good airsoft guns also shoot further than their paintball counterparts. That Echo 1 gun I mentioned has an effective range of around 180 feet with a 1 foot grouping on full auto. My gun can shoot substantially more (but I did spend over $400 on it so its a pro level gun like an Autococker for paintball), a Classic Army SL8 with a stage 2 CA internals upgrade and a 9.6V 2500 MaH battery. That gun can shoot accurately at about 250 feet (but it is the size of a sniper rifle, its just full auto).
It is true that it is very easy to cheat while playing airsoft but the trick is that people who actually take the time and energy to attempt to recreate realistic combat rarely are assholes enough to try to cheap. Airsoft is meant to be played by mature people, or simply with a group of friends that you can trust to actually play by the rules. I think most Escapists would like the level of maturity involved.
And finally, to play airsoft, you dont need a designated field that has been set up and has had giant inflatable things place around to make a great game map. Airsoft simply requires a good old patch of woods. Having 20 people running around in full camo, having to rely on knowledge of your teams movements to tell them apart (not simply which bright color they are) makes for some seriously fun gameplay. Friendly fire can happen but then again it happens in real combat. But it does make you stop and actually watch your target and actually deside to engage instead of simply spraying at the first sign of movement.
Ok my rant is done. Personally I have fun with both paintball and airsoft but Im a huge airsoft fan, and even an officer on my college airsoft team. If you have a patch of woods and a few friends who want to play, give airsoft a chance (and get some decent guns firsto r it will suck). If you simply dont have anyone to play with, taking up paintball and just playing with whoever is at the field that day is great to.
All in all, Im just happy that you want to play a sport that involves shooting another person, because its just so much fun.
EDIT: Also I forgot to mention that good airsoft guns are actually made of mostly metal, so realistic weight and durable as crap.
I think the community for airsoft is also better than paintballing, although paintballing is probably better for a 1 of thing rather than making it a proper hobby.