Biodiesel success stories? Here?
I'd call mine a biodiesel success story. 2003 NB TDI, currently at 22000 miles. About 1/3 total fuel has been biodiesel, in blends from B30 to B100. Switched to petrodiesel last winter (didn't want to risk gelling, didn't feel like driving the extra 25 miles to get it, just plain lazy). No problems at all.
Issues you will want to keep an eye on:
1) cold weather usage - biodiesel gels at a higher temperature than petrodiesel. Petrodiesel at the pump has additives to keep it from gelling. Biodiesel may or may not. Check with your vendor. If not, you'll have to cut it with petrodiesel, or use an anti-gel additive. Search here and elsewhere, and the answers will be revealed.
2) warranty issues - VW claims your entire warranty will be null and void if a drop of biodiesel makes its way into your fuel tank (so some people claim). VW does not (nor can they) warranty the fuel you put in the car (bio nor petro). If you get a tank of crappy biodiesel, and it ruins sensitive parts of your car, you *may* have to pay for the repairs out of your pocket. New fuel injector pumps aren't that cheap. If you get a tank of crappy petrodiesel, you should be able to get the repair money from the fuel station. Check with your local biodiesel vendor as to what, if any, warranty they offer with their fuel.
That being said:
My engine runs much more quietly and smoothly on biodiesel. Between myself and other biodiesel proponents on this board, we have likely over one million trouble free miles between us, at various blends. The only problems (one or two if you care to search the forums) I've seen mentioned here appear to be due to noticeably bad batches of biodiesel. Some people here like to claim that biodiesel will melt your engine if allowed to contact it, or something close to that, but the majority of us who actually use the fuel don't seem to be seeing these problems...
The bottom line is:
Do your research. See what can go wrong. Weigh the costs against the benefits. Take responsibility for your choice, whichever choice that may be. Good Luck.