I know I've had better mileage on 94 Octane over 91 by about 10-12 miles a gallon. Never tried 89-87. As for the brand... You have to gas at difference place in order to compare... Not so sure if the tests are always good ( I think the best word would be a feeling ), as you may get different response due to weather condition ( i.e : Wind ), or riding with other bikes and having to "follow" as opposed to your regular solo riding.
