I read this article the other day. Product Review: Sonax Nano Tech Paint Cleaner (NTPC) – Detailed Image
I read that too but now reading the Q&A at the bottom the answer was in there. For those who were curious: The NTPC uses non-diminishing abrasives, which provide a quicker cut with less effort. Premium Class uses diminishing abrasives so you have to work the polish to break it down before you can achieve as much gloss or correction. NTPC also contains a carnauba wax, whereas Premium Class is simply a traditional paint cleaner leaving no protection (some people will prefer this depending on their desired next step or product application).
Just to re-emphasize, all comments previously are spot on. The NTPC allows someone to continue to polish for longer than the 30-45 seconds typical with diminishing abrasives and still provide a cut. NTPC contains the NanoTech Liquid Wax carnauba wax & the Prem Class Paint Cleaner containes no wax or silicone.