They're cool, but not at all cost effective when you take everything into consideration.
A hand pump costs $60 and sucks to use, and tanks are a solid 400 and cost at least 15 to fill, or a compressor is at least 300. Not very easy to refill out in the field, as even the pump weighs a solid 8 pounds and is big and clunky.
Ammo varies, but it isn't as cheap as it used to be, and the preferred pellets of a few years ago are now as much or more than cheap .22lr. Slug guns are also pretty cool, but shot count is low and they're usually but very light themselves, let alone affordable. Slugs are almost always ¢10 minimum, and range up to about $1.50 a piece of you're buying big bore(just cast your own), so at a point you could actually SAVE money shooting .22lr.
Big bores are pretty sick, especially the .82 AEA Zeus, but they're easily louder than a 12 gauge slug due to the massive volume air dump.
The one advantage is that you can legally install a "moderator" or "lead dust collector" and stealthen things up a bit.
I still like airguns, but only really things like the Daisy 880 for leaving in the shed, or the Diana Bandit for a sneaky sub 30 yard squirrel getting. I owned some medium expensive ones, but ended up selling then a while ago.