My first commercial mower is the exact one that you are looking for (belt-driven, engine type, 36'', etc.) I have had ZERO issues with mine and I have ran that thing through some nasty stuff. It's like a bush-hog and an excellent striping mower all in one. The pistol grips are easy to adjust, maintenance is a breeze, and it'll never quit. The only reason why I bought another mower is for larger accounts. I cut fescue, centipede, and bermuda it does a great job on all. Take care of it and it'll take care of you.
Oh and the one I bought was used and I would've thought it was brand new the way it runs.