I’m playing around with 2.7 and it’s going great! I’ve come across a stumbling block though, in adding my own custom fields using add_meta_box.
It appears that 2.7 Beta 3 doesn’t want anything to do with it, as upon activating a plugin (or adding such a feature into my functions.php) the WordPress installation returns a blank page. Nothing else, just loads a blank page. So I assume there’s an error in there somewhere.