Pot or Reflex Still?
Stills for alcohol range from a simple pot still, which is just a heated chamber with a steam exit tube that is cooled to condense alcohol, to more complex reflex stills, which usually incorporate a fractionating columm to maximize condensation surface area and increase the purity of the finished alcohol.
The type of still you buy is determined by how pure you want your finished drink; a pot still will create a less pure lower proof product, but also let the mash flavors through, desirable in the production of traditional brown spirits: Whiskey, Bourbon, Brandy, and Rum. A reflex still will create a higher proof and higher purity finished alcohol, needed for the production of clear spirits like Gin, Vodka, and the flavored 'moonshine' types you make by steeping fruit and other botanicals in the finished spirit.
Keep in mind you can make an occasional batch of Whiskey or Bourbon with a reflex still, as long as you give the spirit a couple years aging with oak chips or cubes to develop its flavor and darker color. Conversely, you can make an occasional batch of Vodka with a pot still, although you may want to look into a carbon filter to scrub the spirit to remove flavors before bottling. Bottom line - if you prefer brown spirits, buy a pot still, if you prefer clear spirits, buy a reflex still.