I presently am using Yellow Dog. It installs well, but there are a few things that I do not care so much about: Yellow Dog is the Red Hat of the ppc GNU/Linux Distros; and so many things, such as the desktop tend to be what they think is best. Sure you can change it -- often with some difficulty.
On the other hand YD offers MOL in a simple setup so you can run Linux and have a Mac OS9 or OSX in a window at the same time. Near native speeds(?), well, I will say that it is not that much slower than native on a 500MHz G3.
Debian's package manger is better than RPM; but both get the job done.
YD is heavy on the KDE; Debian tends toward Gnome.
Debian supports the GPL more fervently than others, if that is important to you.
In short, you have to know why you are installing Linux. It can be a bear compared to the installation and use of OSX, but it the definitive open source solution. It is a better environment for hacking or just learning from the source (pun intended)
You will notice that I did not say much about Mandrake or SUSE. That was not an oversight.
![Stick Out Tongue :p :p](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)