Roadrunner.
Not so easy to pull the battery on Vipers. Must jack up car, remove rear wheel, slide out battery from compartment. Quite a hassle. Battery tender will not cook the battery. It has circuitry that will reduce charge as the battery becomes fully charged. In case of an emergency, the car is able to be driven if necessary, without 1 hour reinstallation of the battery. You can also start up the car as necessary in the winter to circulate fluids.
Battery tenders are really neat gadgets. Perfect for Vipers in hibrination.