Comes down to fun factor.
GBBR's can be a PITA at times (mags/parts/etc...)...but mostly so because of the way they work. Big, heavy, not-great metal chunks slamming back and forth....they eventually beat themselves to death. And when there's a feeding issue it's often a stop issue since the heavy bolts/parts will mangle the BB and you'll end up picking out the broken bits. Easy to work on when they do need work though.
But the fun in the use of them can't be beat vs. a PTW/AEG/HPA/etc setup. Just not the same.
Mag capacity tends to be real cap...and they work best on semi.
If you want a laser beam, high capacity, potentially-uber-silent rifle then stick with an AEG/PTW. They work, they're simple, they're mild-PITA-fiddly-headscratching to figure out when they break.
If you're the only guy using a real cap gas rifle in a field of ammo'd up AEGs...you might feel "outgunned"...can still be totally enjoyable for some though. But when you're at games where lots/most people are using them...or when the game rules are ammo-limited...then there's really no downside IMO (other than when a firefight breaks out you can definitely hear it and zero in on where it's happening).
More so at indoor places, but when you're at a field game and everyone's using a GBBR it's a very much more so immersive experience than with AEGs.