For what it's worth, most of the older guys in my club use OS 2-strokes or Saito 4-strokes. The younger (or younger in the hobby anyhow) guys have a mixed bag of engines.

I have a SuperTigre G-75 in my 4*60 and it has been an excellent engine. As already mentioned, initial set-up and run-in were more involved than some other engines, but now that it is thoroughly broken in it starts beautifully, transitions smoothly and idles at 2000 rpm or less. I ran it with a 13x6 prop for a while, but it gives better power with a 12x7 or 12x8.