Beat up brass was one of the first red flags that popped up to me when I shot an aquaintance's CETME at the range. The next red flag was multiple fails to chamber rounds. It was his gun and I dont think he throughly cleaned it/inspected it.Great review, thanks for taking the time to post it here.
Century has improved the semi CETME somewhat. Some of the early guns would only take original CETME mags, the H&K's will not fit, which is how original Spainish CETME rifles are. On the other hand, H&K rifles will work with CETME mags.
I'm pleased to see the original type flash suppressors now, instead of those poor quality type compensators they used initially for compliance reasons.
Another thing about the CETME rifle is that they will damage fired casings and make them unusable for reloading. I recommend getting an ejection port buffer as this will prevent the creases from impact with the rear of the ejection port. But there are still issues from the chamber fluting deforming the brass as well. Check out Gun Parts - RTG International Surplus Gun Parts and Militaria for spare parts & accessories.