It's been about a month since switching to Ubuntu. So what do I miss about Gentoo? A couple things...
Last week the repository I was using for my beta Nvidia driver seemed to have disappeared. That's kind of a bad thing. Gentoo was great at having lots and lots of stuff in the main official Portage tree. There are way more things that I'm needing to go to third-party repositories to find in Ubuntu. The more of these I install, I imagine the more likely something is going to go horribly wrong. I'm bypassing any kind of QA Ubuntu might employ on the official repos, and instead blindly trusting that some random guy is smart enough to make a package that's not going to conflict horribly with another package. But given that uninstalling software in Ubuntu actually seems to work, I'm not as worried about this as I would have been in Gentoo.
There's a question of which is better: having tons of highly unstable packages in the official tree which may or may not b0rk your system, or leaving the official tree as stable and tested as possible? I can see an argument for either. Gentoo leans toward the former, and Ubuntu apparently leans toward the latter.
Another thing I miss about Gentoo (I think?) is that in Ubuntu, even running unstable, I don't seem to get updated packages every single night like I would with Portage. I don't know if I miss this, per se. In the sense that it's actually sometimes FUN to upgrade a bunch of packages and see what's new, I sort of miss that from Gentoo. But this may be an entirely masochistic sentiment. I don't know how many updates in Portage were simply corrections to ebuilds, rather than upstream changes; I certainly don't miss Portage telling me to rebuild xine or php or something huge just because a USE flag was added.
A final thing I miss, come to think of it, is running 64-bit packages. In Gentoo I at least felt like the money I spent on this processor was worth something. In Ubuntu to preserve my sanity I run all 32-bit packages. How much difference running 64-bit rather than 32-bit made, who knows. Probably not much. Running 32-bit does save me a lot of hassle, and would've saved me even more hassle in Gentoo I think. But such is life.
What else do I miss about Gentoo? Well, nothing comes to mind at the moment, surprisingly. There are a lot of things I definitely DON'T miss, but that's for another post, another time.