Ever since i put the splits in my truck has had a terrible cackle, loud enough that everybody thought it was gonna blow up. Swithced to B99, cackle pretty much went away. The motor has had a bad shake from 1500-2000 RPM's, which i'm leaning towards injector issues, and when i switched to bio it smoothed out a little. I think i know whats causing the problems, so the B99 is pretty much acting as a band-aid until i can get the problems fixed. Also there is a lot less smoke, and its a lot quieter. Plus it smells pretty good.
Now some downsides i've noticed is that when the motor is cold it takes forever to start up and puffs out a large white cloud for about a second then clears up. I think the crappy cold start is also part of my cackle problem, which i think is low fuel pressure.
On a properly running truck i don't think it'd make as much of a difference, but on my worn out truck it makes some extremely noticeable differences.