I think this is Canonical's most aggressive and unstable plan yet. Mir is baby new, like version 0.0.9. They need to be doing a freeze soon for 13.10 and Mir is still dropping major major features like multimonitor support (soon) and has big performance regressions (some fixed soon). For something being launched to the public in two months, this seems insanely aggressive and unlikely to do well. I'm really disappointed