I have been using an eGo One 2.5ml tank for 7 days as of today. I have went through 4 coils. It has leaked 3 times. I believe I have just ruined another coil due to the tiny tank and not being able to see where the juice level is at. It doesn't produce as much vapor as a Subtank mini or a Lemo 2. Air flow is not what I like. Too restricted for me and that's really saying something as I don't like tons of air. The tip gets hot even with a delrin bottom. You can't completely take it apart for a good cleaning. I'm just tired of it. These are the kinds of issues that would turn a new vaper off vaping. No one paid me to write this but if you feel the need, I'll accept.