In my town we had a VW service facility. I say had, because they just recently went out of business. It was actually a "near-new" used car dealer that was also a VW service facility because we don't have a VW dealer here. Well...
If my experience is any indication, the sentiment in this thread is true.
I took a car in, running terrible, (after lots of effort in trying to find the problem on my own), they said "you need a new MAF", even though I had already traded out the MAF. Guess how much for a new MAF? $330. About $170 for the part and rest to install it. Never mind that I could install it myself in less than 5 minutes.
So I pay the guy. It didn't fix the problem.
After lots of hours looking at it, we finally find that it's a split in a rubber hose, an intake vacuum problem! Should have been easy to diagnose by someone who has the equipment, but unfortunately they are too lazy to give an accurate diagnosis. But, after fixing it they didn't reset the car's computer. He fooled around with it for more hours... I insisted that he give me the car back NOW and get out of my life.
I took it home, reset the computer by disconnecting the battery for some time, brought it back up and it's been running GREAT ever since. I figure they were either totally incompetent, or they were trying to figure out how to zing me for more money.