Paintball is good if you can spend more $$ . . .There are field fees, buying paint balls at the field, co2 recharges, cleaning your gun.
Paintaball is more fun too. . .but airsoft is good on a limited budget. You can get thousands of balls for cheap, you can get decent quality guns for not too much $$, some are manual so no extra expense there or you can get ones that use batteries. There are more expensive airsoft guns of course that use co2. You can play with airsoft in more places since the bb's don't go all that far, whereas paintball you need some serious land to play on.
I'd go with Paintball if I had more time to play with that stuff.