Yes, the first cut after paint still requires a standard 1200 paper, but when going to the next level, these give you a super uniform surface that only requires a very small amount of swirl remover with a random obital buffer.
From my understanding and experience, 3M 'systems' require multiple compounds and polishes to get a glass smooth surface. 3M papers do not have a true uniform grit. 1200 paper may have abrasives ranging from 900-1500 that will leave some bigger sand scratches behind afterwards. I've experienced this many times and that't why I have been using 2000 paper and wearing out my elbows.
This 'new' stuff cuts a lot quicker and leaves nothing behind. The 3M Trizac system was an attaching method for the paper discs and pads, right? I never wanted to invest that much money into a whole new line of papers and pads since I'm not a volume shop. That's why I think this EAGLE stuff is hobbyist friendly. Have you ever looked at the 3M web site and tried to figure out what to use? It's very confusing for the novice.
These Eagle fine grade abrasives leave a lot of room for possible errors and are VERY forgiving. That's the biggest difference I see.
