For a quick guide to the different stills and to help you choose which is best for you see here. For more detail on the styles of distilling see below.
It works by enhancing and concentrating the flavours and aromas as well as removing unwanted sulphur compounds in the large copper surface area of the dome top. This produces a smoother, richer, sweeter tasting spirit.
This is different to a reflux still because instead of stripping flavours to produce a clean spirit, the pot still retains and enhances flavours. This can be used when distilling washes that contain flavours that you wish to retain.
It also provides heads, hearts and tails which you make 'cuts' with by choosing the highest quality parts of the distillation for your spirit and discarding the other parts and/or redistilling them for another batch.
This results in purer, stronger alcohol/higher percentage alcohol. Depending on the level of refluxing, spirit can be produced from 70% through to a theoretical maximum of 96.4% ABV in optimum conditions.
This type of still strips all flavours out to produce a pure plain spirit. You don't need to make 'cuts' on this type of still (only discarding the foreshots).
Is it better to use a Pot Still over a Reflux Still?
All stills collect alcohol from the 'wash' at varying strengths and the total amount of alcohol collected depends on how much is present in your wash.
Reflux Stills collect less alcohol volume but it is much higher in strength. Alcohol should always be diluted with water down to below 50% ABV before filtering.
After filtering and watering down, the total amount of finished alcohol should be the same, no matter what kind of still you have used.
To choose which is best is down to what you're trying to achieve as they distil spirits in different ways under different styles of distilling. See the quick guide above to help you decide.