yeah i dunno about the hp and they keep changing the ratings every year so who really knows? my kawi is 26hp but on the newer models it's labeled as 23.5hp. it's the same engine.
my next mower i'm gonna go with a kohler engine. they seem to do better on gas than a kawi and you don't have to adjust the valves.
i think they all last about the same length of time. kawi, kohler, B&S vanguard, etc.