Wow! The BusyMac folks sure have been busy! I know, I know… I couldn’t help myself. As a BusyCal user for years I’m looking forward to playing with this, it sounds awesome.
UPDATE: Wow, I’m blown away. I imported my contacts from iCloud, Twitter and Facebook. It took me 15 minutes to manually link the few contacts that weren’t auto-linked. Then the Combine Linked Cards view (this should be on by default IMO) made all the dupes go away. So cool!