My area of the country has been on E-10 for many years now and I can tell you for a fact that it works just fine in your outboard. If you research each outboard manufacturer you will find that they all say E-10 is OK but don't use anything higher than that (some areas of the country are selling E-85). It is recommended that you install a water separator type filter and you may have to change the filter several times at first.
Unfortunately there are many unscrupulous outboard repairmen that are taking advantage of the false stories being circulated and tell you that you need certain work to be done. While I certainly don't know everything, I do know that there is only one confirmed problem with it and that affects certain Merc outboards. Merc advises that the fuel pump be rebuilt using new style check valves. If you want to confirm what I am saying, go here: iboats Boating Forums and search for ethanol. iboats is the largest outboard repair forum on the web and have a lot of well knowledged people there.
Fair Winds and Following Seas
Bill H. PTC USN Ret
Chesapeake, Va