I've went through quite a few ego batteries before (recently) switching to a mech mod. Most were name brand from reputable source and a few were no name junk from a local B&M store. The only ones that I have been satisfied with have been the ones from volcanoecigs.com. Knowing what I know now, I never would have shopped there. They are more expensive than many places, few choices, and they seem a bit gimmicky looking back on it (similar to Blu, but not quite as bad). I have bought 4 "Inferno" (ego) style batteries from them. The first 2 lasted for a year charging every day before I thought they were dying and I bought a second set, although it turned out my batteries were fine and I just got a crappy batch of atty's. When I thought my first pair were dying, I ordered a second set. The second set lasted 3 years charging every day. One of them was a pass through version 350mwh and the other was 900mwh. The 900 was as good as the day I bought it after 3 years of use despite being dropped frequently and is only dead now because of an unfortunate accident with my dog's leash which ripped the top off of the battery and broke all of the wires. The passthrough didn't fair quite as well, after about 2 years it had basically no battery life and was only useful in passthrough mode. Most of my time on egos was using smoktech mego dual coil cartos which measure out to 1.5ohms, so I was pretty tough on them. If I were to go back to egos, that is all that I would buy.