I've been using, and have been very happy with, my M401. But, I'm the foreman of a sheet metal shop and I'm constantly on my feet and moving around all day. The M401 hasn't been my cup of tea to use at work. I can't keep it assembled in my pocket due to the auto battery. It activates just from moving around. It gets hot, and liquid ends up in the battery. I have been keeping it in the case (the one that comes with the Dragon from TrueSmoker) with it taken apart. So every time I need a few puffs I have to stop, assemble it, vape, then put it away. It's a pain. I decided a manual battery would be the way for me to go. My next problem with the M401 at work is the constant need to top it off or drip on the atty.
Now, I love my M401. It's great, but not a "use at work all day" kind of great. I am really thinking hard about getting the Janty V2. I have only one question which needs answering: How long do the carts last? I know they are larger than the M401 and probably last longer, but by how much?