If you use in a car that has an engine management system which can make use of the higher octane then you will see an improvement in both performance and mpg. I never use it in the bikes but the cars do benefit, so it's not just a marketing gimmick. You just need to use it appropriately. I reckon the extra mpg pays for the additional cost of the fuel - but in terms of finance it's pretty neutral. The only real benefit is the slightly better performance. It was in a car, a Toyota Avensis. Before I retired last December I was a private hire driver based at Manchester Airport and we had plenty of long runs all over the country. I thought I'd try it out, and it didn't make a bean of difference to the MPG during the month I tried it. Like I said, that was 3,000 miles or so. The one factor that made the biggest difference I noticed though was air temperature. I always had better MPG figures in the summer. I wouldn't have thought 20 degrees difference in air temperature would have such a significant affect, but it did. It's hard to understand when the temperature inside the cylinder is so high, but it was the same every year, though I would add diesel engines were less affected than petrol engines, but the mpg figures always deteriorated in the winter. Yes my himalayan was great on the fuel But summer there was a noticeable difference on fuel consumption!