I've done almost all the upgrades and I can't say it has a good accuracy!
Well that depends with what you're comparing it.... With a stock AEG(with the wisely upgraded there's not much difference at long ranges), then it's better, with a stock Asahi WA2000 (within the range of the stock WA2K).... Well then it's WAY worst!!!
Firstly the "standard" part that breaks... Part91(hop up chamber) this is the easiest to find.
Secondly the sear, well this one is a b*tch to install and after that the problem with the sear adjustment start, if not ajusted properly it will shoot at a max range of 15m this happened to a friends M700.
There are quite a few M700 out there that can't shoot properly even with adjusted sear and trigger!
I've seen a few posts on broken cocking piece, also easy part to find this also happend to a friend.
Peyote broke his sear spring.... Still looking for spare part as far as I know. Everyone tells him to buy a KJW M700 and take it from there!!
(he also posted his problem on other forums)
Well it's late and only these came to mind right now but I'm sure there's more....