I've had all kinds of engines on my mowers. I vote for the Kawasaki. I have a 2009 RZT50 and the engine just runs great. No starting problems, ever. I have Kohler engines on two of my lawn tractors, and they are always breaking down. I only have one BS engine still running on another lawn tractor, so I don't think much of those engines either. I've never had an engine run as smooth as the Kawasaki engine. Guess I'll have to deal with the parts issue, if it ever breaks down, but till then, it's my favorite.
Good luck on your purchase.
Wendy :biggrin: