Not all batteries are created equal when produced in a factory. Some manufacturers, specifically those in Japan, are known to make better batteries with the newest technology - Panasonic, Sony, Samsung, et al.
Andrew Wan is a distributor in Hong Kong who purchases large lots of batteries from the above Japanese manufacturers. He and his staff put these batteries through a series of tests. The highest rated ones get chosen to be sold as authentic AW batteries, get the shiney red wrapper, and get the oval hologram AW sticker. You can be assured that an AW battery will be consistantly a high performing quality battery and be worth the couple more dollars you spend for that peace of mind.
Not to belittle Efest, they make a decent battery. However, in my research on batteries it seems apparent to me that the company overstates their battery specifications to be competitive with the big boy companies. Exaggerated specifications tend to be proven to be true with subsequent bench tests by independent testers. My personal experience with Efest batteries has been a disappointment when compared side by side with AW. That's my

.
The adage, "Never trust a battery with fire in the name" rings true. Trustfire, Surefire, and Ultrafire batteries are second tier name brands. Use these for flashlights, not for mods.
Do not purchase or use non-name brand, generic batteries. These are unknown batteries made by an unknown manufacturer of unknown quality. These are likely to be the rewrapped rejects of other companies, or worse - rewrapped used batteries harvested from old laptop computers. It's not worth the risk using these batteries when used in a mod which is literally inches from your face when used.
There's much more to consider when choosing a battery than just the one with the highest mAh rating.
http://www.e-cigarette-forum.com/forum/batteries-chargers/555999-3400-mah-18650-panasonic-orbtronic-good.html First consider the application the battery will be used; then decide what amp limit you need, and then the mAh rating. ICR batteries (protected Li-Ion) should be considered obsolete in this day of modern battery technology. Their chemistry is not as safe as IMR batteries. They had their day in the sun when they were the best available at the time, but with the advent of
IMR (Li-Mn) and IMR/hybrid batteries that time has passed. IMR and IMR/hybrid batteries are safer chemistry and the only type that we should be using in both mechanical and regulated mods.
Rechargeable Batteries
There is a large list of recommended high-drain, safe-chemistry IMR batteries in the below link:
Battery Basics for Mods: IMR or Protected ICR?
To learn the difference between IMR and ICR batteries, and what the numbers/letters mean on battery models, follow this link:
Deeper Understanding of Mod Batteries, pt I and II.