FreePPP 2.6.2 in general is a major interface and functionality upgrade from previous versions. If you use MacPPP 2.0.1 and MacTCP you need not move to FreePPP unless you want one of its additional features. If your connection isn't broken, don't mess with it. FreePPP works with Open Transport, unlike MacPPP 2.0.1, and it offers lots of features such as intelligent dialing based on your location and auto-detection of modems. I do not recommend any of the other versions of MacPPP that you might have seen.
Full documentation is also available.
Unless you're a system administrator looking to simplify setup procedures or still using a pre-3.1 version of Eudora, I wouldn't bother downloading this version of Eudora Light. I do strongly recommend you upgrade to a 3.1 version of Eudora, especially if you're still using 1.5.x or earlier. New features since then include message filtering, support for displaying styled text, support for plug-ins, support for Macintosh Drag and Drop, active URLs, and a lot more. Note that with this release of Eudora, I'm no longer redistributing Eudora Light on my FTP site because there are several different versions to choose from and some include PGP, which can only be distributed legally to citizens of the U.S. and Canada. You don't absolutely need Internet Config 1.4 if you have 1.3, but it's worth snagging a new copy when you get around to it.