Very quickly, my impressions so far…

• I like WordPress’s admin interface slightly better, though there are some odd gaps (deleting a draft, for example, requires posting it then deleting it unless I’m missing something)
• The default CSS looks terrible on my computer…it looks like ass
• The template system doesn’t require rebuilds like MT does. Instead, you’re coding in PHP, and there is no “rebuild” every time you update a template in MT.
• The WordPress admin interface doesn’t compartmentalize all the editable files as cleanly as MT, but then again you’re really editing css and .php files directly…the flip side of being direct is that you have to be more careful.
• If you’re not careful about being XHTML compliant in your posts, you might lose some of your work :/
• The “Save” button in Write automatically opens a blank post window. I would prefer it to go back to the posts window.
• I like the “edit this” link that pops up if you’re logged in
• If you hate editing the templates via the admin interface, DreamWeaver works just fine!