hmm very curious. My first thought was maybe your mod won't fire sub ohm, but I read its supposed to fire down to .2 ohm. All I can think of now is that your mod is defective since it doesnt work with both tanks.
Second hand vapor may be harmless but it still can be annoying and irritating to others. I sure as hell don't want to be eating my dinner in a restaurant and have to smell some asswipes Tutti Fruity vapor.
I have the eGo one. The coil did come loose a lot when I first started using it. I just tightened it down real good and haven't had a problem since. I haven't had a problem with overheating or "pooping juice"