It's a dynamic mic that requires a very close proximity to pick up well. Not good for a boom, and even if it were sensitive enough it is far too bulky/heavy for boomed use.
The PR-40 has a similar sound and stronger output, but like the RE20 unless you have a body builder as a boom op it's not going to work. And you would still have to be very close so CU only.
If the RE20 was used on location you would probably hear the crane that was holding it up.... and you wouldn't need a boom op you'd need a crane driver.
