I'm not certain what Linux Mint is trying to solve. It's like an answer without a question.
Ubuntu is perfectly fine on its own, and almost all the restricted goodies that Mint adds are in Ubuntu's repositories. The one really killer app that Mint has introduced is remastersys, and you can add that to Ubuntu.
I guess switching from Orange to Green is a competitive advantage.
Now, I have been tempted by Arch, but right now, my Linux desktop is the latest Alpha of Ubuntu. Really nice, 100x better than Gutsy, even with the random alpha errors.