I started with a 14650 E-Power too.
A forum member stopped me in my tracks from ordering a Green Smoke kit and recommended the E-Power, a great recommendation.
There's a pretty big difference between using an atomizer/cart setup and using the dual coil cartos, they're great and my personal favorite 'juice holder', but they really reduce battery life, almost in half from what I've found.
Using an atty/cart, one battery charge would last me 1.5 days, using the dual coil cartos, about 3/4 of a day at medium-heavy vaping.
Great units tho, I think they're one of the best out there for a starter kit.