Blow backs on a AEG ...
Bleh. First off, I've yet to hold one that even remotely feels "realistic", or makes even a realistic "sound".
The pneumatics are "better"... but it's still a waste of space, as it still doesn't have enough "realism" to make em worth it. Maybe, they will improve the system at some point though.
yet, it's becomming increasingly difficult to find G&gs with-out a BB system in em. Seems it' s become a "standard" .. which I find a slight annoyance.
The biggest annoyance, is having to deal with the electric versions when putting the gear box back together. In fact, on mine.. I simply disabled it.
the BB option, does nothing to add or take away from FPs, or operation... save the electric BBs do drain more juice from the battery. ( count on half a MAH per BB fired to be "used". Like 1000 MAH should grant you around 1000 shots, roughly. 1000 MAH with a E-BB feature... more like 700-ish.) Plus, they hammer the tappet plate... why? I dunno, but expect tappet plate repairs eventually.
I say, if you want "realism" buy a decent GBBR ... the We g36 gbbr ... IMPRESSED me.( I now a person that has one... and it seems reliability is one of the best I've found in GBBRs stock, even with the fact, he's been abusing it to try and tear it up to see how long it last. It's a We though, and a gas hog by default.) I also liked the KA GBBRs when Jon let me test fire em... if it wasn't for the other "issues" with them, I'd already have bought one. That's because the recoil on em, even though still not real steel in effect, makes shooting em very fun.
I've "heard" from several pneumatic BB users , that "claim " their BB feature, does indeed sound and feel better , more realism akin to a GBBR. I've actually not personally seen this first hand, or been able to tell much a difference in an AEG that doesn't have BB at all. More sound yes... more realistic feel? Not that I can tell.
But for a G&G AEG, that gun is a nice gun.
I can't say you'd be un-happy with it out of the box.