Well, I've got a working Gentoo system on the Mac now. I got hung up on some Mac-related issues and had to take a step back from it (plus, I've been extremely busy).
Today, I've been letting it compile xorg-x11 (groundwork for running GUIs/desktop environments). It'll soon pass 8 hours of compiling... I just saw a flag stating that it's completed 118 of 133 packages... and I thought the kernel compile was slow (~1 hour on this machine).
For the most part, Gentoo is similar to Ubuntu once you get the system built. However, Gentoo is built from the ground up, where Ubuntu is already packaged and just needs to be copied over. There really doesn't seem to be a 'right' or 'wrong' way to do it... they are just different ways to get to a similar end, each with pros and cons.
Certainly, I hope most of the larger packages to install won't take over 8 hours to complete, but really, I am almost working with an antique (~7 years old, ~300mhz PPC)... so it's no wonder that compile times are through the roof.
I will say this for Gentoo -- it is an excellent distro and a great learning tool for getting more knowledgeable with the inner workings of a Linux/GNU setup. There is great documentation to get through the install (Gentoo handbook) and some good stuff I'm just getting to in their wiki. Plus, you can optimize out the wazoo, as everything is compiled from source (with flags you can specify).
Also, if you are going to install Gentoo, do a stage3 install from the terminal. The first time I tried Gentoo out (on my Desktop), I went for the automated install on the liveCD. Not only was I a bit confused as to where some of the inner workings were located and how the package manager worked, I also lost interest pretty quick too. Building it manually lets you get familiar with the 'how and why's as well as giving you a sense of accomplishment when you get it working.
If you want something that 'just works', stick with Ubuntu/Debian/Fedora/etc. If you want to get your hands dirty, even if you're just curious, give Gentoo a try. I might try a x86 install in a VM (Virtual Machine) just for the heck of it.
Well, the compile passed its 8 hour mark and is up to package 123 of 133. Should be done soon.