The Power pallet from All Power Labs is unquestionably the best gasifier in its power range for the money. APL is really close to having the unit just be a plug and play appliance and they are still making improvements that can be added onto earlier models. They just lowered the price for the 20kw unit to about $25k. It will run continuously at 16kw for days at a time and the units can be grid tied or paralleled for larger industrial power needs.
That kind of investment pays back quickly if you are:
a. off setting 20-30 gal/day of diesel for a 20kw diesel generator
b. already buying power at peak hours
c. having shutdowns from an unreliable source of electricity
d. you're paying for the transport and disposal of a woody bi-product (nut processing plant, stone fruit cannery ect).
I'm originally from Berkeley and Oakland so I've got a little pride.
If you only need to run your water pump at 3 hp once a week or it's for home power outage the power pallet might be over kill
Charcoal Gasifiers are also very cool, look up the crossfire.