I found Derek Sivers’ post on ditching Rails interesting. He spent two years trying to reimplement the code for CD Baby in Rails, abandoning PHP, and then abandoned the Rails project and rewrote his old PHP application in PHP (its original language) instead. From his list of reasons, it sounds like he made the right choice.
Perhaps he should have read Joel Spolsky’s essay on the dangers of rewrites before getting started. Interestingly, you’d have to say that Joel was wrong in chastising Netscape for rewriting Mozilla from scratch. Nothing as good as Firefox could have been written using the existing Netscape Navigator code.
By the way, PHP’s autoload feature looks like a lifesaver.