I got my WE M4 a few weeks ago. It seems really solid and it's really fun to shoot! Nothing as happened so far. I've racked the charging handle many times and so far it seems to be holding just fine. I haven't put many rounds through it yet, but i'll keep you guys posted if anything happens too it. Can't wait to skirmish with this beast of a gun. I'll be getting a G&P rail and a G&P ACOG. Hopefully the ACOG can handle the recoil.....
Matt