Don't really know what the differences are, but I just finished a trip from SoCal to Arkansas and back. Got Bio Diesel at a couple of stations. I did notice a difference with mileage. With the Bio I got under 10, #2 as much as 12.8. Not a big difference, but noticeable. No difference in the way the truck ran or sounded. 2014 Duramax and a Jayco 321 RLTS. Given a choice I would avoid the Bio just because of the mileage difference. I have also heard it is not good to let Bio Diesel "sit" for longer periods of time. No idea if that is true or not.