I'd just like to point out the difference between protected and unprotected batteries. Protected will cut out when the volts get too low - like an eGo battery which still has enough power to brightly flash the light to warn you it's too low but won't supply any power out to your head. Unprotected will run flat like old style batteries we used to use in torches etc until they went dim and eventually died.
Modern batteries can't be allowed to go flat cos the chemistry inside them has a fight and burns the house down next time you try to charge them, hence the protection (protected batts also have overcharge protection). However Vamo's and Provari's have their own built-in protection so they'll stop the battery from getting too low for you. I've also read of some folks having trouble using protected batteries in Vamo's, something to do with the two protections fighting each other.
So, for a Vamo you're better with unprotected batteries, but get a good quality charger so they don't get overcharged, and don't use them in mods without in-built protection unless you learn how to tell that they're getting low and recharge them.