I don't have the 2/3 but I do have the slightly updated "RX Gen3" which is a full-time 3-battery mod that has a few upgrades over the 2/3 like 2A balance charging. It is amazingly small for a 3-battery mod and it has excellent build quality - feels really solid. I have been using it with my iHeat with ArcticFox firmware and I am really happy with it. I am running straight TC, no preheat or anything. Wismec has also released a 21700 and 20700 version of the RX series as well, if big batteries are your thing.