In the few years I have been engaging in E-cig use i have seen the technology improve dramatically. It has come to a point now finally when I no longer experiment with new hardware as it has come to a level of efficacy that I no longer want anything else from these devices. I like rebuildable tank atomizers (RBA) because i dont like purchasing coil replacements. I make my own coils it takes only a few minutes and they last for a long time. My wicking of choice has become japanese natural untreated cotton. My two favorite RBA's are Kanger Subtank mega which is great because you can use it in both rebuildable mode or with prebuilt replacement coils for convenience. Also love the already classic "Kayfun 3.1" or "The Russian" excellent performers and solid construction.
I use these on a Hanna Mod DNA 30 or any DNA 20 or 30 chip variable voltage/wattage device. If anyone is interested in learning about this crazy world of vaping and there is ton of info out there try this site Taste Your Juice | Can I Taste Your Juice? this guy has so many detailed reviews on anything you might encounter related to ecigs. Enjoy