The original formula is superb for straight razor shaving IME, especially if you like thin, slick lather... It's the antithesis of modern U.S artisan stuff. On the downside it can be quite drying, due to the relatively high essential oil content probably.
The premium range is a different formulation which is more of an all-rounder, thicker lather with more nourishing post-shave thanks to the addition of shea butter.
I like them all but if you mainly use safety razors I would advise you to skip the originals as they just don't have the required cushion and the post-shave is a bit lousy. Stick to the premium range and you'll be a happy shaver.