I'll always go to AEG, I've owned my fair share of GBBR's always end up selling em and picking back up an AEG. GBBR's are big money pits and if you dont have the funds to keep em aloft then AEG is your best bet.
I always broke it down like this:
AEG + Mags = $250-300 gun + $60-$80 10 mags
GBBR + Mags = $300-$500 gun + $400 10 mags
Polar* is an option if you want to save money on mags, but then you have to buy a HPA tank and the kit itself costs $550-$700 depending where you get it from.
"Don't you know the first law of physics? Anything fun costs atleast $8"