I run it in the FFV Explorer and in my GAS ONLY Focus.
Over 130K on the clock, been running E85 (straight and mixed at various ratios) since the warranty ran out 70K ago. Not a single problem, no issues, no regrets.
Ford's E85 strategies on the FFV Ex's are OK, but there is a LOT of room for improvement. Focus picked up 6 HP with nothing more than swapping fuel and the flash.
Don't buy the lies, use GOOD fuel and E85 from REPUTABLE pumps and there won't be issues. Use cheap gas and the E85 will pull all the moisture out of it, separate the alcohol from suspension and mess up your day.
I start with small doses (10%, 15%, 20%) and increase until I trip a CEL (~22% Alcohol) and then go straight E85 - that way the water is all burned out.