I got mine just last week(first GBB), and found that hop up setting is terrible. None of my shot is anywhere close to target, or maybe it's partly because the bolt blows back before BB leaves barrel. It's still something I have to get used to and do some more adjusting on the hop up.
Anyway, still pretty happy with my Garand, except the wood fore grip is extremely loose. After, dismantling almost half the gun, tighten up most of allen screw, and realize that front outer barrel wasn't screw all the way in. So during reassembling, I have screwed it in all the way, now the front fore grip is tight.
Btw, suggestion to ppl who just receive their Marushin M1 Garand, make sure all the screws are tight. I have found quit a few loose screws on mine, probably due to anti-rust oil they use at factory and vibration during shipping.