When you try doing something you’ve never done before, you expect things to go wrong. In the case of that SimplePie class I was talking about, the difficulty was just finding the correct download link. Once I had the correct link and the class was successfully installed, a quick test script I wrote actually worked first time (once I’d corrected a couple of silly typos).
The real test will come later, when I upload everything to the web server. But for anyone writing in PHP and needing to read RSS and Atom feeds, SimplePie is the tool I’d recommend.