OS X Package Management I'd like to know if anyone out there has done a comprehensive comparison of the various package manager solutions available for OS X.
More specifically, I'm looking for:

A list of all the major package managers (ie. MacPorts, Fink, etc)
A pros and cons list or comparison matrix (either self-written or a web link to one)
Information about any caveats for particular systems
Information about possible incompatibilities or reasons for not having multiple package managers installed simultaneously
Subjective reasons why you think one is better than another

Update Nov 29, 2010
Chiggsy gave a great answer but I would really love some more input on this.  I've been using MacPorts recently and it seems to be pretty well done.  I like that its command line options work in a similar fashion to subversion and that it has an interactive mode.
Homebrew


Easy to use
Always up-to-date
Easy to extend (Github-based)