I've used both Efest and AW 18350 IMR
batteries. The Efests began to give out after only a month's use. I get 5 - 6 hours good use with the AW's in both a Mini Provari and a Smoktech Gripper mechanical mod. More consistant in quality battery to battery.
Ignore the high mAh ratings of Trustfire, Ultrafire, & Surefire
batteries. These are a second tier quality battery that overstate their capacity to encourage sales away from the better brands.