• The install procedure was more painful than it had to be. Despite installing in a fresh directory, I had problems with default templates being missing.
• Akismet still isn't part of the default anti-spam package - why is this? The built in logic does a decent job, but the collaborative filtering provided by Akismet is far and away a better solution.
• The new authoring engine is quite nice. I keep finding small niceties as I need them; for example, the bottom of the text area I'm typing in has a grab handle that allows me to resize it as necessary.
• The meta-soup of tags, keywords and categories hasn't been unified yet. I realize people have probably created their own ontologies by now, but Melissa's tag cloud is empty because she always uses categories - every heard of a category cloud? 'Cos I haven't.
• The new templates are lovely, and well-organized. I'm looking forward to building a new site or two based on MT as a lightweight CMS thanks to the new page templates.
• Comment handling still seems to have some issues. The 'Report as Spam' link in emails I receive from MT is as likely to take me to an error page as it is to work properly.

Clearly SixApart has their work cut out for them, but I'm still pretty happy overall. Kudos to the MT team for the release.