What Michael said, only the longer version.
Most newer vehicles run fine on gasoline with ethanol in it, but it has less "bang" so mileage will be less. The percentage of ethanol and price difference are the key to which is better for a vehicle that is in constant use. The ethanol free places around here charge about the same price, but there aren't very many.
Ethanol creates some problems for vehicles not in daily use or if stored in cans for use in small engines. It will absorb water from the air while the ethanol also evaporates. A sitting tank of gas starting out at 10% ethanol will become about 7% water, so it might be worth buying straight gasoline for your motorized toys or the spare truck.
PS: Most marinas carry only ethanol free gas.