I had a decent experience when buying my pre-owned car at this dealership, they were friendly, though the deal I got was not the best- probably my lack of bargaining skills, so I don't fault them for that.
The issues that I did experience after purchase is the need to replace my brakes a mere 800 miles/5 months after purchase. I had taken my car in to get serviced for a noise and upon inspection, my brakes were found to be at the wear limit. The mechanic said that it is highly unlikely that they were a-okay when I bought the car and should have been replaced before the car went on the lot for sale.
After voicing my complaints to Mercedes for this issue, I was offered to have the breaks looked at by their guys- too late though as I chose not to drive with worn breaks and had already gotten them fixed. No other solution to their mistake was offered other than condolences.
I would not be careful when buying pre-owned cars from this dealership as it is evident that their safety and repair standards are below the industry standards.