I have a kawi, good engine.
Its very powerful in the low revs, I will say it is a bit particular about how you use it. It likes a very particular start up procedure or it chugs alot. Seems like a very good engine. My mower was bought second hand and I know it had a hard life before and after I bought it. It must have done hundereds, probably nearing if not in the 1000s of hours. I came by it because the previous owner had smashed the gearbox in. Just shows the kind of abuse its put up with and it still sounds great and doesnt smoke atall. It burns no oil and is very powerdul, I would possibly add that it seems more powerful than my same HP briggs engines though if you over do it it lugs very quickly whereas the briggs are harder to lug down.
I use it everday very hard. It doesnt miss a beat going full tilt across newly ploughted areas, its still runs fine after being rolled while still running, I just resatred and drove back. The biggest probelm I have is its habit of stalling when going up hills in high gear towing something, the briggs dont stall out, must just be nature of the beast. it is also set out poorly for serviceing, but they may have addressed this now, it is a '89 engine I believe. Another thing is that it uses unusual spark plugs and it can get pricey compared to the briggs.
Having never owned a kohler i cannot compare but general concensus around my area is that both are good engines but kawi are just that little bit better. Around here its easier to get kawi parts, but I accept that it is vastly different where you are.
I hope these comments help /forums/images/graemlins/wink.gif