The E10 is a bit unfriendly to the polymers in your fuel system, so they won't last as long. This is an issue to collectors and people (like me) who use old mowers. It isn't really an issue to people who buy Bunnings mowers and toss them after a few years, as long as they don't store fuel for long periods. Ethanol absorbs moisture and goes yellow: at that point it has a few extra undesirable effects.
The 95 octane petrol is a bit different chemically from the 91 octane stuff we use routinely, but that is a different kind of issue compared with the E10. Essentially, with the 95 you might find yourself having more gum formation in the fuel unless it is fresh.
To put a scale on the problem, imagine the worst outcome: E10 that was 95 octane. At that point you'd be in approximately the situation the US is in with its heavy use of octane improvers as well as ethanol in the fuel. You'd need to add a stabiliser if you left fuel in the tank for months at a time, and you'd have to expect fuel system problems (replace diaphragms, hoses, seals etc) a lot sooner than we are used to.
