Basically, the control panel needed to be smooth as a sheet of glass - any imperfections were going to be very apparent.
I would agree with this ... almost -- you need to get ithe surface smoooooth (and then it is beautiful)!
If you are refinishing an old CP, then strip it right down to the metal, getting rid of the remnants and gunk (you should do this anyway).
If you are working on wood,then it is a little less lovely, but get it smooth and it will be fine.
I've used it on 4 metal panels and 1 (well, 3 ... 3-sided cocktail) wood panel with no complaints (but I like the results on metal MUCH better).
So long as you do a decent job of cleaning up, it should be fine.