i was going towards gtting a dual 18650 mod, then i realised they were all serial connected batteries, need to keep them in pairs, from new. i suppose the better dual chargers would keep them close enough, charging cut-off equally, but it's an added concern.
Then i found that the custom box mods i was looking at, like the Ranger, are all variable voltage, not variable watts. i don't want to get into that either.
Maybe i'll choose between the IPV2 or the fasttech HANA 50W.
I was on the same buzz with the batteries... I actually watched a few vids of the MODs that takes dual batteries and most of the reviewers say that the battery life isn't as long as what people think its going to be, especially if you're vaping high watts.
So i think i will settle for the IPV2S mostly for the charging USB port