I've finally switched over to a 50/50 mix of 100LL and 91 Mogas to save some money. Seems to work fine, just doesn't smell right. 100LL was $6.55 per US gallon here last week. Premium Mogas is a "good deal" at only $5.25 but I hate hauling it out to the airport.
I've pulled back the power a bit in cruise these days too, 25/4600 gives 135-140 knots TAS.
I'm starting to think the RV10 was not the best thing to build now.
My way of dealing with this is just not to look at the credit card slip any more. Fill 'er up and enjoy the flight.