i hear that u better get ready to change alot of fuel filters since they plug up sometimed depending on the % of the blend (from a pump)
other than that its pretty much fine to use as far as on-road trucks are concerned from what the O&O trucking magazines i get
check land-line magazine and other similar publications for alot of info into biodiesel
if ur thinking of converting a truck to run on used vegitable oit then ull have to figure a way to heat ur fuel tank to keep the fuel from gelling