Hi..I'm still fairly new to vaping but I'm getting tired of eGos and Spinners. I bought a Bolt and I love it. Simple and uncomplicated, that's for me! I've been looking around for some different styles and sizes of mods but most everything has the bottom firing button. Why is that? I did buy a Seiglei but now I'm having issues with the button and anyway, it really has too much info for me. Is the Bolt the only side button simple mod out there? What's the advantage of a bottom button?