Perl is great, but then only when someone else is programming it. During today's investigation with the new MT 3.1 code tree and with great pleasure, I delved into the "mt/php" directory.
Dynamic Pages are a feature of MT 3.1. They are implemented with PHP. What I did not realize previously is that the good blogging folk at Six Apart had done what appears to be a nearly complete port of MT from Perl (bless it) to PHP. This port appears to include support for all current MT tags, it relies on Justin Vincent's ezSQL DB library and Smarty templates, and even supports a plug-in API. What we don't have yet is the publishing API or interface in PHP. Perhaps this will arrive in the near future, perhaps not. The implementation of the author interface is really not a great concern for consumers. What matters there is that it works.
On the tech implementation side, this is great stuff. The port to PHP combined with [experimental] support for page level caching is one giant step forward for MT as a content tool kit.
Everyone doing anything serious with MT was doing it with PHP templates already. Anyone with significant amounts of posts was starting to hear the rebuild (static page generation) process creak, groan, wail, and occasionally utter a final sigh.
This port makes perfect sense. It relieves the problems of massive rebuilds and lays the bridge across the chasm between archaic Perl CGIs and the world of web applications. Bravo SixApart.