I forgot why I quit looking at them. It was the efficiency. Even Bloom Energy (SOFC) is only getting 50-60%. They are selling the electric from their systems for 8c/kwh which in some cases is cheaper then grid supplied electric, but it is above the wholesale price. They also take time to heat up slowly to reach production temps.
The PEM looks like it can only use hydrogen since it is Proton exchange, which is still in the same efficiency range, but it can't use syngas only hydrogen. There are some that look like they can use methanol however direct methanol fuel cells are extremely inefficient. But neither is going to work well with syngas.
Now that being said, the SOFC 50% efficiency for syngas looks a lot better then running an engine for woodgas for standalone generation. You are getting close to turbine efficiency without the hassle of running a turbine. It wouldn't work for vehicles very well because you need a constant flow to keep the temperatures correct and they can take an hour to heat up to running temp. So you need to use it to supplement power, or pair it with batteries to get optimal efficiency for the system.
if the 2-2.5x density battery packs that samsung just announced available in 2021 for cars are the solid state ones they worked MIT on. (5 years is about what it takes for NHTSA to approve new techs.), They supposedly will do 100k charge cycles, slightly lighter, don't start fires, run at -40 temperatures, charge faster (although not super fast) and are still 90+% efficient. Which means after the car poops, you can potentially still have 90k charge cycles left on a 200kwh battery pack. Which pairs well with the SOFC and woodgas.