I have one myself, I use it to hot rod a .25 size balsa wood model instead of spending a lot trying to find a 25FX-AX or .32 SF/AX. FP 40's are everywhere for around $40 these days.
It's a great engine for a trainer, helps the beginner think ahead of the plane, easy to tune, focus on flying more. Light weight, no ball bearings to rust out from neglect. Did I mention they're $40?