I am giving this shop an average grade, its not great, nor is it bad, just ok.
First impressions are good, clean shop for an older mercedes repair facility. I was greeted promptly, but not 'friendly'. My father-in-law goes to this shop and it is fairly close (as can be in Northern Virginia with traffic). Told them what needed to be done, and to do an overall look over of the car.
Did they repair the car, yes. But their work isn't 'clean' as I would like--which makes me suspect of the work that was performed. For example, there is a wing nut on the air filter cover. I know it was there because I inspected the air filter prior to taking the car in for repair. When the car was returned the wing nut was missing. I asked where was it? Was told we don't know, and you don't need it anyways since you have two clamps holding down the air filter cover. Seriously? You couldn't get a $.75 cent part and put it on to satisfy the customer? He did not accuse me of saying it wasn't on there to begin with--but just that you don't need that part. So, what other parts don't you need when you're fixing my car and not replacing because you forgot to put back on the car?
Secondly, as I inspected the work that would be visible, I noticed they didn't put on the extra belt that was previously missing. I pointed that out and was told again, you really don't need it as there is one already there and the other is extra. Again, really? You think Mercedes Benz just put an extra pulley and belt there for the fun of it. There wasn't a, "Sorry, we'll put one on there right away" or anything--he just looked at me with a blank stare.
The work that I was having done was on an older Mercedes, having the timing chain guides replaced. As they get brittle when they age, and can cause catastrophic damage if they break within the engine. The timing chain will lock-up and basically making the engine inoperable without an expensive rebuild. So, what did you not put in that repair because 'it wasn't necessary'. I don't know because I can't see their work.
The car runs fine, but what surprises await because of shoddy work, I do not know.
Go somewhere else.