I'm using MarsEdit 1.0, connecting to my WP 1.5 gamma server via wp-xmlrpc.php and I can add new posts fine. However, editing posts is borked. If I edit, it throws an error, and bumps the post into Draft mode (so it disappears from the public side of the weblog). I've filed a bug on it at:
But I was wondering if anyone has had better luck?