The performance issues with Safari in Leopard and Flash video was really starting to get on my wick. There seemed to be some kind of memory leak, and required Safari to be force-quit after some limited time.

Thankfully, this seems to have been resolved with this update.

On a more general note: I love Flash. Its cross-platform nature, and Adobe's move into HD video, means that more people will be able to get video in the way the publishers intended. Every platform has a level playing field - and for once, content makers have an effective way to distribute their content using a platform that isn't Real or Windows Media. It may still be proprietary, but at least all platforms are covered!