To me, the holy grail was to find a rebuildable 
tank atomizer with no or minimal leaking. Once I bought and started using KFLs my search was over. The KFL is my "on the go" "all day" atomizer. A full 
tank lasts me about a day and the flavor is fantastic. I find it to be simple, reliable, and easy to build and use. There are other great RBAs and of course the new 
kayfun v4 but I'm so content with my KFLs that I'm not at all interested in spending money on the newer stuff at the moment.