Paintball, in my opinion, has more ability to sport team work.
Airsoft-not painful enough, there is no reason to be suppresed when nder suppresive fire
Paintball- Lets just leave it at "OUCH"
Airsoft- BBs travel up to 100m, meaning you don't have to use your team mates as much to get the job done
Paintball- You have to work your way up to the opposition, with someone covering your ass
Airsoft- Realistic looking guns
Paintball-There are different designs of hoppers that don't stick up in your face, and c02 has it's place on the guns design, they don't get in the way, they give you a but stock, or an extra handle
Airsoft-can be damn expensive [I could buy a car for some of the prices on those guns!]
Paintball-can be very expensive, but 85% of it goes into ammo, not a gun that you have to pay an extra 200$ on to get some power into it [Airsoft]
Paintball- Can still get realistic markers.
As you can see, I would take paintball over airsoft any day.