In order to have certain sidebar widgets show up on only certain pages and categories, I'd been using a combination of a PHP code widget and Widget Logic. Now I've found http://wordpress.org/extend/plugins/section-widget/, which seems to be able to do the same thing more simply. I've got it running on one site which has ATA 3.4.2 and WP 2.8.4, and it seems stable.
Anyone else try it? Any problems you've noted?