Water use is a very fair attack of biofuels, in general. Land-use is as well. Making biofuel from existing celluosic feedstock, like corn stover or other wastes, is generally fine in this area. Swithgrass may not be, however, depending on where/how it is grown. This is one reason why closed loop systems for algae growth (to produce biodiesel, perhaps) are interesting to me.
i have no problem with biodiesel technology. some of that makes a lot of sense. i have no problem with anything that might work, but i just dont' see it in ethanol and a lot of the support and the ethanol mandate seems purely political.