In particular, they are far and away a better option than hydrogen, which I have previously groused about here, here, and here. The American Scientist piece explains the obvious and straightforward benefit of electricity over hydrogen:
Indeed, one of the great advantages of plug-ins (and purely electric cars) is that they can directly use solar- and wind-generated electricity for transportation, a process that is three to four times more efficient than converting such renewable energy to hydrogen for vehicular use.
As I've said many times, hydrogen is not a source of energy, it is a particular means of storing and delivering energy. It just so happens to be a terrible means of storing and delivering energy, because it requires a lot of waste and creates all sorts of technical difficulties. As such, I simply can't see any future for it.
The real future of the automobile will be the electric car, with plug-in hybrids as the transitional species. Anyway, the entire article is well worth the read, so hop to it.