As a pretty frequent System One user, I'll chime in with my $0.0002 (after taxes). Todd is pretty much on the mark for System One use. It's a great product for someone looking for a good 1 step (especially one that can be used in the sun). It does produce dust. So do most products out there. However, the dust is non-abrasive like a true compound (3M Extra Cut for example).
At the BMW shop, I use both literally every day. The dealer is a 3M believer, but also recognizes System One as a "good" product. If I'm on a time constraint to get a car done quickly, System One is the product. If the car is going to inventory (especially black cars), 3M is what he requests.
Case-in-Point: I recently did a black BMW 545i that was very scratchy. Lots of wet sanding, then 3M Extra Cut (started with wool and switched to foam for better results), then 3M Dark Glaze, then 3M Ultrafina SE, then
Meguiar's #26. A power wash was done between each step. This took 3 complete days and the car is 100% scratch-free.
Right after that, I started on a Black BMW 550i that was lightly scatched (car wash swirls mostly). The dealer got a phone call from a potential buyer that was coming to the shop from out of town and wanted to see the 550i. So, I started at 6:00am with System One. I finished the car with
Pinnacle Souveran for depth at 2:30pm the same day (the buyer showed up 45 minutes later).
545i Time: 24 hours
550i Time: 8.5 hours
Both Cars outside
Partial sun on the 550i
Not-so-sunny shot of the 545i
In person, there is better depth of color on the 545i. But, I compensated for that with the use of Souveran on the 550i.
The dusting issue applies to almost every cutting product out there. 3M produces a very abrasive dust that MUST be washed off before proceeding to polish (or you will re-introduce scratches from the residue). System One dust is a non-abrasive powder that you can continue to work on the car and use a foam pad for polishing. In my working environment, that's a big time saver.
I believe Tom has introduced a product that new as well as seasoned pro's could use effectively.
Hope that helps you fine folks.
Totoland