The new extensions use the full features of the Dreamweaver MX architecture, and are thus more easily updated, faster to insert/update/delete from pages, and more versitile.
The new Preview Refresh button on some of the extensions allow you to see what the link is going to look like with less trial and error. The preview is right on the extension interface:
Turning Translators On and Off
Also, a new feature allows you to turn off the translators used in the design environment. Translators are nice in that they give you a graphical representation of where the code is going to appear on the page, rather than a script shield. But they tend to slow down Dreamweaver MX on pages that are extremely complex or on very slow machines. Now you can toggle these translators on and off by choosing Toggle Translators from the Server Behaviors >> DWTeam >> Recordset Navigation menu: