I have an eleaf istick 30w with a Nautilis mini, and love it. I use the mini because I like the 2.5mL to have a variety of flavors at a time. I am wanting to get another so that I can have two flavors going at a time, so I thought about getting the 50w for battery life. Bit I read it has it's issues, and to go with the 40w that does not have issues. I also read of some other batteries outside of the eLeaf brand that may be better. I think I want to stay with Nautilis for the tank, but have never tried anything else. Does anyone have any insight as to the best choices to assist with my decision?