MAF is the Air Mass Meter, this is simple a sensor that sits between the air intake and air filter, it measures the air density and temperature, and send those signals to the cars ECU, which in turn then can subtly alter fueling and air to get the best performance, mixture etc.
However they are simply a series of hot wires, that stretch across the sensor (if im correct) and can be very fragile, they are usually ok if they dont get knocked about by something, they are so fragile they have even been known to appear at dealerships broken when spares have been requested.
But they are an astronmically expensive part for what they are, and when they go wrong, the car tends to perform badly.
For some dealers it also seems to be a problem to diagnose, we all know what it is and usually the symptoms, but they tend to only read off what a silly computer tells them rather than actually earning their money and being a proper technician every once in a while.
But again if you took a comparison of all the car owners here, its a fairly rare occurrance, certainly not as common as the coil pack fiasco, and your new car shouldnt suffer from any coil issues just to set you right on that too
