My buddy bought a Ferris with a Kwai engine and had a pretty major failure in the first hour. Covered under warranty obviously...but still happens. A lot of people assume Kawi engines are the best OPE engine out there but they can have issues just as easily as any other. My experiences with Briggs have been great personally.
35 hours on my Ferris with the 25hp Briggs. 3 year warranty on the engine. I try and mow when dry(tough this year) and I do think it clogs up to easy. Other than that it does great in my farm yard. The only thing I need to get is armrests for it.
Exmark owns the zero turn market and would have one in a second but the slopes I have make zero turns not an option. Picked up this JD X758 last Thursday with 42.9 hours on it. Hydraulic AWD with Yanmar diesel. Marches up and down the hills with no issues.
Being pretty good friends with a power equipment shop, they aren’t shy to tell me how it really is. Kohler is by far the most problematic. Briggs vanguards are solid motors, especially the big block motors. They still prefer Kawi out of them all. Scag is still king in my opinion of the zero turn market. Their cut quality is among the best and their layout/build construction is the most well thought out in my opinion.