Ethanol Confusion

For a couple months now, the gas stations where I usually fill up my tank have psted a sign saying,
"Up to 10% ethanol"

I have read the arguments that ethanol has less heat value than regular gasoline. However, my 2000 Saturn LS1, 5 spd manual, seems to have more pep and pickup on the ethanol added gasoline.

Anyone else have similar experience, or contrary experience, or explanation?