Usual Tokyo Marui quality and it's surprisingly weighty. Mine chronos at 224-230fps on 0.20g bbs with the hop off and the full auto fires at 12rps.
Battery changing is simple and easy. The top slide pops off, the battery is inserted under the barrel. It even has a little lever to push the battery out to change or charge it.
Aep's are not as realistic as gas blow back, as they have fixed slides and no recoil but the lack of recoil does give the advantage of steady aim.
For full auto use I would suggest investing in 100 round Mags.