Our '96 E300 Diesel has been in two accidents; both wife-induced rear-enders.
The repairs made at a collision shop that specializes in this work have been flawless. This shop does Mercedes-Benz, Porsche, and Ferrari. The car is cannot be seen as anything but 'zero-time' but it is not original. More
importantly, we have driven it 30,000 miles over the past year without any regrets and with few problems. She has a long commute, and we love to drive it!
In my opinion any car that has been properly repaired is OK to drive. The key is proper repair, including measuring multiple points on the body to check for 'bent frame' which is really a torqued body shell.
A good collision shop can probably give your potential car a look-over to spot replacement parts, and can measure for proper body alignments.
So, you could have a Technician check the mechanicals and a collision shop check the body.