lack of power is definitly NOT an issue with the 13.5 hp unit we have. The first time I have a guy use it instead of me it nearly jumps out of their hands and probably would if not for the kill switch, We have thick st augustine grass here and sometimes I will smoke the belt a little, I just slow down a bit and it solves it. The only issue I have is in a real thatchy spongey st aug lawn the lowest pulley on the cutting blades will actually be touching the ground when running the machine and I think that causes belt slip. Probably not an issue on cool season grasses. Overall I am very pleased with this machine.