I tend to be a fan of methane for its high hydrogen content per unit carbon as well as how much easier it is to store than hydrogen. However the argument against methane that I do find convincing is that the infrastructure for transporting and distributing methane leaks a lot. The argument is most compelling against residential distribution, where maintenance is harder to justify, but large leaks regularly occur, and that is very bad for greenhouse emissions.

I’ve always been curious about generating methane in industrial composting or from landfills and using it onsite for hydrogen generation. Not sure if the generating capacity is enough though, there is probably a reason it isn’t being done.