If you are processing a 5 point protein unit, the length of time sounds about right. It takes me about 3 days to process a 5 pointer on my G4 933MHz.
As for which of the F@H programs to use, I would say that they are all the same. The big advantage that you have by running the command line version or the graphical client, is that you will be computing more often then with the screensaver.
A neat thing about running these clients under OS X is that, even though your processor usage is maxed out from folding, everything is still as responsive as without running the client. Because of this, download the command line or the graphical version.
Hope this helps.
Later,
Draft