I'm not as hardcore as those who enabled natty repos shortly after maverick was released. However, I have been testing Natty since Dec 3rd -my 1st full Ubuntu testing experience.
It has been frustratingly fun...I only had 1 critical breakage which required a re-install - which was my fault.
Submitting bug reports has flooded my inbasket with fellows testers from around the world.
Using unity from a horrible mess to a usable "whyisthisinplaceifitisntanybetterthanGnomedesktop " utility has been quite peculiar.
I hope compiz, unity, and ubuntu tweak learn how to exist in harmony. I have given up on plymouth, as is seems to be worse in natty than lucid.
The 2.6.38 kernel is incredible compared to 2.6.27 (Ibex), when I 1st installed ubuntu. The sound, performance, and fun factor are a helluva deal - FREE!
I wont do anymore testing until 12.04 (Prolific Pangolin??)...I will reiterate to Ubuntu beginners that testing releases is time- consuming and frustrating (but fun if you like to diagnose and fix your PC). Do not ditch your stable releases for development versions...and,if all you can offer are complaints, it's a good idea to stay with stable releases.