There are choices to make when you buy a Provari and I can understand why they do it in a menu of choices. Some people already have the IMR batteries and a charger, others want a different battery size and don't buy the extension cap ... or they do. You configure it like you want it and the total changes as you pick and choose.
I'll admit that I carry my Provari only when I feel I can safely watch out for it and keep it safe. It's fine in a pants pocket and I can turn it off if I want to prevent actuation in my pocket. When I cut grass, the eGo is in my pocket with the switch turned off.
I'd recommend the 18650 battery option with the extended cap. You get the other cap for the shorter batteries anyway when you order the extended, so you can use either battery. I wouldn't want less life than the 18650 provides. It's an all day vape option at 2000mah.
I may order a Pila charger later. My Trustfire does fine in a put in, take out, charge more later mode. When it finally turns green, my voltmeter shows 4.1v. If I charge for an hour, take it off, and continue when I return, it turns red and starts charging again. It's looking for 4.1v. When that happens, it turns green.
The Provari is a precision made PV. It's stainless steel with excellent machining on the entire surface, including the threading and designs on the caps. It's heavy, but that's what you get when you use hefty, solid materials for construction.