I had a major power steering fluid leak on my 94 E320 years ago. The fix was easy because it was caused by a bad shaft seal in the power steering gear. A two hour job of disconnecting hoses, removing the power steering gear and replacing the seal. The bad side is that the fluid leak destroyed the rubber of the control arm bushings directly underneath the steering gear, and I had to replace those also.
Recently I replaced all the PS hoses and the seals in the PS Pump, another easy job. No more PS leaks.
In my opinion Power Steering leaks are not something that should prevent you from buying an MB.