It's been a great big win on Jellybean, so far.

Test-first is probably the largest benefit, though breaking up my plans into stories, then into tasks, and then implementing each task as simply as possible helps too.

The design is better, I have more confidence in the code, and I spend less time stopping and restarting the server to test a new feature. It's also a lot easier to improve the code without worrying about breaking other things.

Just this afternoon, OeufMayo and I tracked down and fixed a couple of bugs because we can both run the unit tests... and we're in completely different time zones. (He's a francophone, and I have my own little piece of paradise in western North America.)

The instant feedback is also nice.

It's not working so well on translating Rogue from C to Perl, but that's probably because I'm stuck on the dungeon-generating algorithms. They're rather hard to test.