I've found that gas mileage is a lot more sensitive to throttle position with the top off. I am assuming, therefore, that when wide open, this sucker can really dispose of fuel. It seems to be faster in the mid range as well (and thats all that really matters, no?) . But around town, where the opportunity to squeeze the throttle is more frequent, I got a tankfull below 25 mpg recently. But on long hiway trips, at constant throttle, gas mileage is just fine (in fact, I set a new high at 43 mpg for a tank).
Also with the full face helmet, I don't notice the high frequency noises, but there is a low freq that is really nice, on full throttle at about 5k rpm.