Primitive upgrade path from Views 1. This is not well tested, but may be found under the Tools menu. (Thanks KarenS!!)
Clone a view
Live preview
Some handlers from comment, poll and statistics are in.
API: Views can handle external data sources if they're described properly (thanks hunmonk!)
Enable/disable default views
Major bug fixes
PHP4 basically works but is not thoroughly tested.
Lots and lots of little bugs fixed
This is a rough list of features NOT YET IMPLEMENTED and thus TODO:
PHP Arg code
Relationships
Filter groups
Edit locking [because of the way the view is stored, it is possible and wise to lock a view from editing while another user is editing it. This lock will be overrideable in the event that someone is a dork].
RSS
Validation, lots of validation
Handlers: profile, book, taxonomy, search, upload. Plus, not all handlers from node/user/comment/statistics have been implemented yet, but lots are.
Javascript to make fields de-activate when they are not relevant
Initial release of Drupal 6 version of ATCK. Lots of changes related to the Drupal end of things, per the radical changes to the theme layer -- but happily the underlying layout engine (based on Yahoo Grids) did not require any changes at all. :-)