I have 2 of these mowers and have been using them for 18 months mine do not have the blade clutch though as i just see that as another thing to brake - the first one i bought has maybe 2000 hours on it now and the engine still cranks up first time everytime, maybe this is due to changing the oil every 7 days. what has gone out on it is the rear wheel drive, i have spent maybe $200 trying to fix the problem and i now have a working drive but its not really strong enough to pull the mower - so essentially it is now a regualr push mower. i repalced the drive belt and whole transmission assembly, i dont know what else would cause the drive to weaken the wheel gears and bearings all look good.
In my opinion these mowers offer a great cut quality, they are efficient on gas and reliable for an affordable price, my understanding is that the difference between these and a full commerical model is the transmission, which explains my problems. but hey after 2000 hours for $600 id happily buy a new one every 2 years. Money well spent if you ask me.