Isn't there a problem with the ethanol 'attacking' some parts of the fuel system or is this just restricted to bowser dispensing systems?
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Overall it's great but there is a big issue: ethanol. The STC limits ethanol content to 1% and you often find that 91/96 UL fuel contains more than that. The UL engines (Rotax) can take up to 5% and you never know what the ethanol percentage will be. At our aerodrome, it ranges from 0.1% to 2%. When it's above 1%, I mix with avgas to keep it below 1% (more or less). For this to work it is important that your airfield always accurately determine the ethanol content after each delivery and clearly indicate it.
I'd tread carefully there. While I have no experience with 91UL, I do have experience with what ethanol in car fuel can do to your fuel system. It's not a pretty sight, the stuff eats the fuel lines from the inside. At some point, fuel can't get through anymore. Annoying in a car, potentially deadly in an aircraft. Make sure not only your engine, but your entire system can use the stuff.