I would say just snag an MVP, but I've been rocking a KFL+ nano on mine recently and it's way too topheavy to bring out and about. Switched to the SVD but that's a ..... to carry around even in 18350 mode (and a measly 800mah). After lots of research, I'm goin with the Cloupor DNA 30 to rock my kayfun. The things is sturdy, wont wobble/tip over a lot with a hefty tank on it, decent locking and screen, and passthrough so you never, ever have to worry about running low on battery at work as long as a usb cable is around. The Sigelei 50w/IPV3/100/150 watts etc etc all look sexy and nice and im sure are cool for dripping, but for the kayfun you really don't need anything above 30 watts. IMO, anything above 30 watts is pretty unnecessary (depending on your resistance of course). For like ~30 bucks more than the MVP, the Cloupor basically kicks its ... up and down the street