I can third this observation. I've even had my flat above one of these for 10 years. Small company, privately-owned, five employees or so. They have a few pick-and-place machines (SIMATICs as far as I have seen) located in a small factory building and manufacture small production runs with them.

They don't have a real website advertising their services, but they seem to do well, probably their customers know them. They've run their business continuously for at least those 10 years I've lived at that spot. I could smell the soldering oven running constantly.