I love these guns, I've owned at least 5 of these guns. Always end up selling one then going right back and buying one. Hell even Janus has one of my old ones lol
But as a first gun I wouldn't recommend it, it really is just a gigantic m4 with a huge mag. A&K/CA uses a proprietary gearbox but everything inside is V2 even the nozzle. If you were going the G&P route then that thing actually uses a V2 gearbox, safety doesn't work on the G&P models though.
Also external parts are readily available and all fit on each other. Mine currently is a CA base with a G&P fullstock, Star/Ares Top tray with rail and a G&P rail system on the front.