Century Int'l Arms seems to be the source for those CETMEs. I've read of some problems, but most seem satisfied with the rifles. The most common problem is a barrel not correctly "timed" to the receiver, so that the front sight is canted a few degrees left or right of the barrel centerline. The result is a gun that cannot be made to shoot to the point of aim, or require excessive windage correction when adjusting the sights. The problem can be corrected.
The CETME "clone" rifles are built on one of several types of receivers; mostly the stamped steel or the cast stainless steel. Both work, though the stamped version is made by Hesse Arms (or whatever name it is using these days) and there have been dimensional errors reported. If you check out a CETME, try to insert and remove a magazine. If the magazine binds and must be slammed in and removed with a mighty tug, it's probably a Hesse receiver.
The cast stainless receivers look pretty much the same, but seem to be of higher quality. That receiver was originally manufactured a few years ago by Special Weapons, LLC and the design, I believe, was sold to Century. There is also a cast aluminum H&K/CETME receiver which is ugly as sin - they have been improved lately (appearance-wise) but can be identified by the integral scope mounts. For not much more money, you can do better.
If you really want a HK/CETME type rifle, there is a screaming deal available right now at Federal Arms. They have the CETME rifle assembled on the stainless steel receiver for $299.95, and they throw in five magazines (Item No. RI1073X). Call them at (763) 780-5747 and ask for Harlan. I have no stake in their business, just a satisfied customer passing along what looks like a good deal. It's a "limited time offer", though - so don't wait too long if you want one shipped to the FFL of your choice.
If your tastes run more towards FALs, Harlan can help you there, too. Federal Arms has the matching-numbers Austrian StG-58 parts kits and Imbel metric receivers. Can't go wrong with that combo, and the guys at the FAL Files message board will help you out immeasurably whether you build it yourself or decide to pay someone to do the tough part.