Depends on when they were made, really. The ones from the early '50s suffer from a lot of the same issues as other "occupation" guns did, namely a metal shortage, cheap materials, and untrained workers. The late '50s through the '60s ones are as good as any you will find on the market today mechanically. Finish was sometimes a different story.
Any of them from the mid to late 70s should probably be avoided. They tended to "Alec Baldwin."
The hammers could "bounce" if the gun was jostled hard while being carried with the hammer down, or if the gun was dropped (I guess some people didn't know that they should be carried on an empty chamber). More troublesome, the hammer could trip without the trigger being pulled regardless of what stop the hammer was on. This meant that it was dangerous to load them with the hammer back on the first click.
They got sued into oblivion in 1980 as a result.
Weirauch bought the tooling and started making two versions of the revolvers. One was a decent Colt clone made on a Zamac frame, and one was a really good one on a steel frame.
I've had a few of the Sauer ones through here, some E&M marked. Most were pretty good, but some looked to have been painted with oven paint.