What issues are you referring to? I have a TM G36C, and modded it into a full-length. Most of the internals and externals have been totally replaced, and I haven't had a single major issue yet. I say major, because I have had the small hiccup here and there, but nothing that wasn't caused by me. Aside from Tokyo Marui, Jing Gong, Classic Army, and Star make G36s, and a few other lower-quality manufacturers as well, so if you describe these issues you've heard of, it'd help.
It's all fun and games until someone gets hurt...and then it becomes sport!