I’ve been playing with both S1 and S2 style systems now. The S1 system is actually much simpler; in it you are basically adding flesh (HTML code) to a standard skeleton. In S2 you are writing a small program that generates HTML. The main problem with S1, for me, is that it limits you to no more than 50 entries per page. Plus it doesn’t have much support for non-English languages AFAICT. Also it does not support tag views, such as what you get right now if you go to http://fonts.chemoelectric.org. (This is likely to be changed soon to take you to the same place as http://fonts.crudfactory.com.)
If you were going to have making LJ styles as a hobby, you’d almost surely have more fun with S2, in part because it is easy to give the user a bunch of customizing menus of your own design.