I've been using the AW IMR's (14500, 18350, 18490, 18650), some for over a year now. I recently went against my normal policy of only purchasing the AW's, and bought a couple of 14500 Efest IMRs for my daughter's AltSmoke BB and a couple of 18350 Efest IMR's for my Mini Provari.
After about a month's useage, both of us noted similar battery life as our AW's for the first three weeks, but after that the battery life has dropped severely from 6 - 7 hours down to 3 - 4 hours. My Efests are now collecting dust in a drawer, not worthy of being in my AW rotation.
If it was just one size battery, I could rationalize that I got some from a bad batch, but this was with two different battery sizes. I purchase all of my batteries from RTD Vapor, a trusted online battery vendor. We both use Nitecore Intellichargers, a high quality charger.
I have AW 18650 batteries that are over a year old that are still working nearly as good as new. I've never had a bad AW; makes me wonder why I chose to try Efests.
Just my experience.