I am playing with gentoo on my laptop for about 3 months. Today i decided to do an emerge system.
It is really easy to update it: emerge –sync followed by a emerge system (you can also use emerge –pretend system first in order to see what it will be updated) and finally a etc-update.
Everything worked as expected. The next step is to do an emerge world….. But i am sure it will take 2 days to finish. The last compilation of kde took about 1 day 🙂