The best in what way? Easiest to use? Thickest hits? Fastest heatup time? Best for vaping on a windy day? Best for cold weather vaping? Best for stealth? Even for stealth, it all depends on where you are and what you're doing. There are flame powered vapes like the VaporGenie, butane catalytic (iolite/WISPR), battery powered (Solo, MFLB), etc. There are so many different types of portables now, you need to specify what features are important.