I also have the B&D "Powerfile" as linked above by chris.s. I really do believe the name really is a red herring as you cannot - at least I cannot - get the same accuracy, flatness/squareness as I can when using a proper hand file. Apart from anything else, the side-mounted motor, and the overall balance of the tool prevents it being used as one would a proper hand file.
OTOH, there are some jobs that you just can't get into with a proper file, and mine does remove material at a reasonable rate in such (rare?) cases. The tracking/tensioning stays reasonably on target, belt life is OK, and belts are a reasonable price (both the narrow and wide ones - I have total 3 arms, and mine did come in a blow-moulded case - it that's imprtant. The pot metal arms are perhaps a bit on the weak side, but handled with care it's OK (back into it's case after use).
Not something that would really class as a professional tool (like those seen in vehicle body shops, etc) but for the hobbyist/DIY-er needing to "get in there" on difficult jobs now and then, IMO, it's OK.