Tank miles are a fairly meaningless measure, because the point at which you stop to fill up again is highly variable. I fill up at 11.1 gallons sometimes and 8.9 gallons other times. Many will say that going close to empty is bad for your fuel pump, which is cooled by the liquid surrounding it in the tank.
You could compare to a strict 10 gallon fillup, but then you might as well just go back to talking about miles per gallons, since now you're talking about miles per ten gallons, and that's just moving a decimal point.
On E85, driving like a maniac, I get 220 miles per ten gallons, driving carefully and sticking to the speed limit I get 310 miles per ten gallons. Similarly, on 87 pump gas driving like I normally do, I get 310 miles per ten gallons, while driving carefully I once got 440 miles per ten gallons of 93 pump gas. My top miles from a tank thus far was just over 500 miles... but that was going much closer to empty than the ten gallon line.