I just installed Mandrake 9.0 last night along with win98 and winxp all on the same drive. It works well. Just have a partition or drive free and it'll install no problem!
The only thing I could do without is the dual-dual boot thing. I turn on the PC, it goes to LILO. From there I choose Linux or windows. Then I get to the windows bootloader that lets me choose between win98 and winxp. A bit of a pain, but I set the default for LILO to go to Windows so it will eventually go into winXP by itself if left alone for about 10 seconds.
I tried Redhat a while ago, but thought Mandrake's install was a little bit better IMO. But Linux itself is about the same. You get basically all the same packages.