Israel:
Good question. For me it's the shear volume of woodgas I can make. My hydrogen electrolysis experiments haven't yielded engine capable volumes. A wood gasifier uses about 60 watts to power a blower that can pull enough gas to run a respectable genset. This is the chemistry approach to hydrogen. Say 20 cubic meters of gas per hour at 20% hydrogen is 4 cubic meters per hour
If you have a good means to make H2 from electricity I am very interested. I have seen people use carbon (soot) and aluminum oxide mixed into water to make hydrogen, but you need the aluminum. It would be nice to use solar panels to make clean H2. I would mix my hydrogen with plastic oils to make storable diesel instead of the storage tank method.
There was a story about a university using a AAA battery to split water. Pretty cool.
http://news.stanford.edu/news/2014/august/splitter-clean-fuel-082014.html