I will never use it simply because there is FAR too much gas in e15. e10 and e0 are even worse! E85 only for me. Much cleaner exhaust and much cleaner burning with increased performance. It is too bad that we are mandated to use 15-30% gas in our ethanol!
No e15 for me, not ever!
I will use E15 in every vehicle I own that's eligible (all) because it is the best fuel available.
E15 is a no-brainer for anything with computer fuel injection. I have used mostly E50 in a 1992 Toyota 4x4 since April of 2001 and E30 in a 1995 Ford Aspire since August 2002. To do these mid blends, I splash blended E85 and E10. It is ridiculous that E15 or 20 didn't happen years ago.