OK, we'll try to distill down the discussions that have taken place on other forums after some folks managed to obtain this European only formula here in the USA.
This is the first product that Meguiar's actually developed outside the US. It was still created by our chemists here in Irvine, CA, but we actually shipped our lead man for the project to Europe, along with a mini lab set up, so that he could quickly respond to testing and inputs and tweak the formula as needed. Pretty cool stuff, actually.
* What is M101 designed for? Rotary buffing with a dedicated foam pad on European aftermarket (ie, body shop) paint.
* Why "European" aftermarket paint? Because, unlike factory paint which is the same whether the car is sold in Europe, North America or Asia, aftermarket paints vary in different parts of the world. It's a high solids versus low solids situation with these different paints, and that can require different compound formulations to achieve maximum results. Oh, and for the record, factory paint is vastly different from a chemistry standpoint than the paint used in a body shop. If a body shop, whether in Europe or North America, were to shoot factory paint it would virtually never cure due to a body shops inability to bake it at sufficient heat and for sufficient time. It's just not economically feasible for a body shop to have that sort of equipment.
* Why "dedicated foam pad"? While use of a wool pad is commonplace here in the US for sanding mark and swirl removal, in European body shops they almost never use wool. And rarely do they compound the entire vehicle - it's mostly spot repair following a repaint, and it's almost always with a foam pad. They also tend to run the rotary at fairly low rpm. So we've developed a dedicated foam pad to use with this compound, taking into account the cultural toward low speed rotary and anti wool bias.
* Why did we send a chemist and mini lab to Europe? Lead time, really. Imagine if we sent product over there, had it tested, then had to tweak and send a new batch across the pond, repeat, repeat, repeat? It would have taken months. And we couldn't do the testing here because the aftermarket paint used in Europe is very different from that used here, due to environmental regulations.
So basically what we have here is a product developed for a very specific type of paint system and a pretty specific work flow. That a handful of guys have imported this back to the US (it is made domestically, just like all the rest of our products) and are finding success with it using either wool or microfiber pads is interesting, to say the least. At the moment we have no solid plans to introduce this product to the US market.
as usual so many factors, depth of defects, hardness of clear coat.... we are not using 101 on its own. Initial prime and then adding either 105 or 300 as needed. Then 101 as boaster per Kevin. 
