instymp, they are all just classifications of different tobacco types.
Different leaves cured in different ways have different flavours, that's all.
If you don't particularly care which type they are, as long as you like them, then that's fine.
I personally find the differences between them pretty easy to pick out but I can see where others can have trouble.
Carter Hall, Prince Albert, Sugar Barrel, Sir Walter Raleigh, Velvet, Granger, and Half & Half are all cut from the same cloth. They are different types of burleys, which is a type of tobacco most famously found in Kentucky but it grows all over the world. These American blends usually have a bit of sweetener added but they are otherwise fairly plain tobaccos.
Wessex Burley Slices, Solani Aged Burley Flake, and a whole whack of C&D burleys such as Haunted Bookshop or Old Joe Krantz are just examples of burleys done a different way.