I only ever use Tesco momentum (which I think is 99Ron) I've been using it that long that I couldn't comment on the difference between this and standard fuels, I do seem to remember that it did last slightly longer between refuels (considering for the same £ you get slightly less fuel as well being more expensive).
Either way its only 4p more than the standard and if it does go further (If you believe the marketing) plus keeps your engine cleaner then I consider it worth it.
I'm sure everyone has their own opinion its just from my experience
