In my experience (had 2 custom knobs for my SSV and used to switch them to my LSV for the decorative look) the default knob is best knob. You handle this vape ALOT, having something decorative and oddly shaped on it is like putting a jewel in your sword handle. Maybe it is for some people who are very careful or don't use it constantly, but for me I like it clean and efficient. As to people's questions about keeping it from rolling, I used those livestrong style rubber bracelets to make a heat-shield/rubber-foot for my unit that works wonders. Good for passing to people who don't have forge tempered hands, they just only touch the rubber. I just took a picture because I am too high to explain the setup I think.
Also, all that blue stuff on the cord is electrical tape. I made a cord protection mod by wrapping the base in electrical tape, then one layer of wire wrapped coat hanger in a spring type shape, then an outside layer of electrical tape, then some zip ties just to keep everything clean and in place. Hope this helps people decide what model suits their needs. Kinda wish I had bought mine when they offered black.....