Its much cheaper, supports very high compression (actually enough to offset most if not all efficiency loss VS pump gas), and if your car is NOT a "flex fuel" vehicle the computer will not richen the mix up enough to hurt MPG, Less carbon build up in combustion chambers, smells like pop corn, supports american farmers instead of saudi terrorists, helps engine run cooler, can make more HP because it carries more oxygen into the air fuel mixture... heck the only good reason I see to not to is because al gore likes it.

I put a bunch of fuel system parts (steel lines, t-quad float bowl pieces, aluminum, brass, 68 cuda fuel hose...) in a sealed jar of e-85 and now 15 years later it all looks the same as when I put it in so I don't buy that the ethanol is what is plugging stuff up, ethanol actually leaves zero residue when it evaporates. If you keep the moisture out (don't put it in a boat or something with an atmosphere vented cap that will sit a long time) it will not corrode anything up,.