I have a few complaints about this particular gun.
1.) The Battery compartment is small, can't use a large battery.
2.) It has a 2 piece hop up, and tabbed upper, those tabs break all the time and the two piece hop up is a pain.
3.) Front end is proprietary, you need a special JG upper to mount them, not so much a problem as it comes with one, but if one breaks, gotta buy one new.
The only major thing about JG s-systems I like, is their powerful JG blue high torque motor.
I like to advise King Arms sportlines when you're on a budget, had one and it did me very well.