Like many gbbr's the lm4 has its pros and cons, but for a beginner gbb user its a great platform as its one of the better pick up and go platforms out there. Mags can get expensive and if you have alot they tend to get heavy on your kit but are one of the better mags out there if not one of the best and is close to or atleast on par with ghk g5 mags. internal wise there are a few things that could have been designed better such as hop up, a steel buffer lock, and a one piece upper but overall most of the really important internal pieces are already stock steel so you dont have to worry about replacing those. I recommend you go to the kwa lm4 forums as they will show you all the mods and the ins and outs of the lm4 and how to maintain it. Overall I say I'm very happy with mine and I would recomend it.