I make and run 100% most of the time in my 6.0 and have been for over 7,000 miles. The only problem I have is a little hard start first thing or if it sits for 8-10 hours on a cool day. I cycle the key twice and it usually starts up fine. It would be nice to figure out why as it doesn't do it on dino diesel but the cost savings overshadows the little bit of inconvience. My truck is also noticably quieter and runs alot smoother. You just have to check each batch for soap and total conversion. My daughters boyfriend says the exhaust smells like tacos.
Dave