Some Hesse receivers are fine, others are not. No easy way to tell just by looking. Headspace can be checked easily enough, but other problems are more easily diagnosed with a firing test. One common problem is an out of spec ejector block placement which can cause the rear of the mag to sag and bind on the bolt hold open pin resulting in failure to feed. It can also cause unreliable ejection.
I've got an FAL built on a Hesse that works well enough now. It took larger than normal locking shoulder to get headspace in spec, and it also had the sagging mag syndrome which was fixed by adding a bead of weld to the mag release. Now that those issues have been corrected, it works. I wouldn't avoid one just because of the Hesse name, but I'd make sure it's a good enough deal to account for the possibility that a few shortcomings may need to be fixed.