Whether E85 is worth it or not is more of a regional thing. When the price spreads are there, it can be a plus to use E85. When we had our insanely high gas prices a few years back, I used E85 exclusively. With over $1 price spread and only a 3-4 mpg hit, it was more than worth it.
EPA claims that emissions are cleaner from ethanol fuels. I really don't pay much attention to that stuff. I don't live in a major metro area. And I did live thru the 60's / 70's, and air is a lot cleaner now than it was then, in just about every part of the country. Whether the mix of ethanol in gas contributed to the pollution decline, I have no clue.
I keep waiting for one of the OEM's to finally jump on a engine specifically designed for E85 and not just these either / or flex fuel engines. Cummins has had a 2.8L inline 4 E85 engine for awhile that has a power output equivalent to the 5.7L Hemi engine, and gets almost diesel equivalent fuel economy. Ricardo played around with a V6 E85 engine that could almost match a 6.6L Duramax in performance and fuel economy. They ran it in several 3500 GM pickups. When the engine is designed to take full advantage of E85, it can be a real eye opener. The BTU level of a fuel is a factor, but other characteristics of the fuel, when taken advantage of, can make the BTU equation moot. And even in the flex fuel engines, they seem to be somewhat dependent on the design and ECM parameters as to how much affect there is on fuel economy between E0 and E85. My 2015 2500 6.0L will average around 14 mpg for all miles on regular. It averages around 11 mpg on E85. Regular E0 gas is going for about $2.51 in my area now. That would be roughly a 18 cent a mile cost. E85 is going for about $1.75 in my area. That equates to a 16 cent a mile cost. Hadn't looked at it for a while. May need to go back to E85.
Putting E85 into a engine primarily designed around gasoline is a total waste unless the price spreads are good.