Cheap ones...
I bought a Sears one, and it was useless for fine work.
Make sure any one that you buy has a "teasing" throttle... some of the cheap ones are either ON or OFF, with a small kick back as they spin up... this makes it difficult to locate a hole precisely.
Also, since all of the power is back in the compressor, go for the lightest one you can get....
gil in Tucson