Kohler 4-cycle engines compared to Briggs & Stratton

I'm not re-powering. I just noticed that some of the Lawn-Boy mowers at Home Depot come with Briggs engines and some (I'm thinking the newer models) have Kohler engines. I figure they must be struggling after being forced from using their own two-cycle engines. I'm actually pretty happy with my three year old LawnBoy with a Briggs engine. I was thinking of getting my Dad a new mower and was wondering if anyone had first hand knowledge/experience with the new Kohler-equipped LawnBoy walk-behind mowers (or any mower with a Kohler engine). Neither one of us are hard on mowers. Heck, I had a Craftsman mower with a Tecumseh engine I used for 12 years. And it wasn't the engine that wore out on that machine. It was the aluminum deck that finally broke apart. The only think I've ever heard about a Kohler engine is that that don't perform well if not on level ground. That wouldn't be an issue at Pop's place.