I've had my B450 brushcutter over 15 yrs and this machine could run for a good 8hrs unstoppable cutting sakati, which is called in our native thick sord grass in our island. And each time we perform our jobs I have no worries. I don't even have to change the scorpian so often. Also, using blade not a problem. Need fire wood, the blade could cut down to it's roots with no hestitation or stalling. This product is rated at five star. All Shindaiwa is #1 in commercial product. And I'll be purchasing a new one on this up coming July 4th from the dealer.