I've never used Turtle Wax Color Magic, but I'm a big fan of Meguiar's products including Scratch-X. I used NuFinish ONCE and threw it away because it was so hard to remove the one time I tried to bring back a neglected paint job.

I recently bought the DA Power System and was extremely pleased with the results. I didn't bother paying extra for the kit with all the polish & wax since I have plenty of that - I just got the (overpriced) $55 kit with the head & a couple bonnets. Even though I already had a good buffer, I especially liked this because I ignored their advice and used it with my cordless drill. It was so convenient to not have to drag around a cord. Another reason to like it is because the bonnets are really small. Whatever time you might lose due to the smaller surface area, you make up by getting into tighter spaces and because it's easier to control you get less products that dries chalky on textured trim.

To bring a neglected car back to life I would wash, clay bar, rinse/dry, polish with buffer, wipe off with soft terrycloth, wax with buffer & wipe off with terrycloth. I keep the vehicle in the garage so I can spread all that out over a few days. But then... I tend to go a little overboard when it comes to detailing.