E85 is widely used by performance tuners as a cheaper alternative to race fuel. With it's 105 octane rating, and availability at many gas stations across the country, it is becoming increasingly popular in performance circles.
As a daily driver fuel, I agree it hasn't lived up the hype. But as a race fuel alternative, it's pretty baddass.
With respect to corrosive properties, modern fuel systems take to alcohol based fuels very well. We've done many E85 conversions, without seeing degradation of rubber o-rings, seals...etc. E85 is becoming a viable alternative to expensive racing fuels.
The drawback, is you need to upgrade your fuel system by at least 30% flow (larger injectors and bigger fuel pump systems) in order to offset the reduced energy contained in a gram of E85 vs. a gram of premium petrol.