I have about 5 hours on the motor at this point and am still in the process of breaking it in. First impressions are that it runs about like a gasoline powered motor, it takes a few pulls when cold to start, needs to be choked for a while until it warms up.
The best thing is the lack of exhaust odor, much cleaner burning than a gas engine. The throttle response seemed a little tricky going from idle to running, it stalled a few times until I learned to increase it more quickly that my gas motor, other than that I am happy with the motor.
It does use more fuel that a gasoline engine I would estimate about twice the amount. I got about three hours of running from a small 5 pound propane cylinder, but that was running slow speeds during the break in period. I would guess you could get about 8 to 10 hours from a 11 pound twice that from a 20 pound at 1/2 throttle.