I haven't personally run mandrake, but redhat was OK. I still never got over using rpms, I usually just installed the source packages anyways. When you feel good enough, come over to debian, with apt-get and you will be hooked for life.

I would recommend you getting familiar with redhat or mandrake, I think it probably doesn't matter much in the long run, they both can run the same apps, the only difference is probably in the installl, and I can believe that they both are pretty easy to install now of days.