Efests would be one of the last battery manufacturers that I would purchase from if given a choice. They are notorious for misrepresenting their batteries' true specifications, and advertise specs much higher than their true specs when compared to independent bench testing.
Purple Efest Batteries: Not As Advertised
There are only a few battery manufacturers in the world who make their own "cells". Opening a new battery manufacturing plant is an extremely expensive undertaking (multi-millions in dollars), and the top brands make their own battery cells. This would be LG, Panasonic, Samsung, Sanyo, and Sony.
All the other brands on the market can not afford a new manufacturing plant, so they buy the second and third tier cells from those manufacturers and re-wrap them under their own brand, but these are "second and/or third tier cells" which did not meet the higher standards of the original manufacturer. So, in order to compete with the original manufacturers' batteries (first tier), these other companies feel obligated to publish specifications which are inflated to make them appear superior to those of the original manufacturer. No, that's not honest, but that is the reality in the battery market.
* (AW is Andrew Wan, a former Panasonic employee who branched out to create his own "brand" of batteries. He allegedly has agreements with the major cell manufacturers to purchase first tier batteries from them. Not all batteries are created equal, so AW tests these batteries for quality. The best get chosen to be AW brand, and are re-wrapped as "AW".)
I ask, why pay more for a pretty wrapper or inflated specifications for a battery which is actually a second or third tier battery, when in most cases you can pay less for a first tier battery from the original manufacturer?
Do your research before you buy. Decide what battery to buy depending upon the application that you will use them. What is your first priority besides safety? More amps or more mah? Mooch has done independent testing of many of the batteries available to use; look for the results for the top batteries you are interested in in his
blog.
I have devoted a lot of time and research into the batteries available for vaping:
Battery Basics for Mods: the Ultimate Battery Guide
Deeper Understanding of Mod Batteries