Well i can talk from a perspective of someone that has spent thousands on mag fed paintball and eventually switched to airsoft.
Milsig MRK II, rifled barrel, bore sizing kit, HPA. Probably one of the most accurate paintball markers on the market. After that in a straight out accuracy test, i could hit maybe a 2 foot target at 20 yards. The rifling of a paintball barrel does nothing for a sphere full of fluid, it will go the way it wants to. And putting balls in a mag will dimple them, causing even more inaccuracy. One way that i found you could get around this is using powder balls. Almost as expensive as first strike. And equally not bio friendly. Bio friendly fields will not allow first strike or powder balls. (pretty sure powder balls are only made by one manufacturer, they can set the price they want.)
The pros of paintball. ( and sometimes also the cons) Here are some thing that i miss from paintball since switching to airsoft.
-You can always tell when you hit someone. (usually because you are so close to them you could walk over and point it out.)
-The loud bang (I miss that a little)
-Most paint ball markers need to be charged to work. Unlike all AEG's that work as soon as you switch that selector.
What i love about airsoft.
- Reaching out and touching someone at 90 yards. (Yeah that feels good, and having a grouping less that a foot is awesome)
- The gear is way better, and not covered with slime.
- guys with Nods...i mean that's cool.
- The equipment works better. ( i don't know how many times a team member was down for a game because something went wrong with his, seals, remote line, cylinder, spring. ( not to say airsoft doesn't have its own equipment failures. but they seem to just be few and farther between.)
And a mess of other things other people have said in this post.
Both are fun. And truly the secondary line of equipment is similar in both. I would say try both out.
A problem is a chance for you to do your best.