I visited this thread in 2017 looking for someone's experience in running e15 but rather, found people saying not to do it because of this, this and this. Basically what you can find on any Google search.
So I decided to test it myself. From 2017 to current. Only used E15
2008 Ram 5.7
Starting mileage: 128,030
Current mileage: 136,654
Oil: Mobile 1, changed every 3500miles
1 throttle body swab and seafoam treatment.
Climate: Midwest, Iowa, humid summers, below 0 winters
Usage: Every day driver until May 2019. May 2019 to current - only used for towing/work.
Towing: 10+ times <4000lbs. 3 times >4000lbs.
Payload: 10+ times at 50-75% capacity.
0 problems, no knocks in the motor,
0 heating/cooling problems.
0 corrosion problems, the only thing thats rusting out are my damn wheel wells. Per usual.