I believe Koen is on the optimal track for reliability, ease of operation, weight, and system complexity. Others have pointed out quite correctly that the energy losses from burning off the hydrocarbons are arguably unacceptable, as was the conclusion of government regulators in northern Europe in WWII.
Koen is pursuing secondary chemical processes to recover some of those losses. In temperate zones though, I envision the perfect marriage - a stationary simplified gasifier designed to slip the char and burn any tar in a close coupled gas stream for heating and supplying hot water. If 5 cords of firewood are needed to heat a home here, then WAG, closer to 8 or 9 would be used if burning primarily the hydrocarbons.
That would result in a pile of charcoal sufficient for a lot of driving, or tractor work, hopefully even excess for biochar.
Regards,