Actually CompanionLink doesn't do the same thing. CompanionLinks is very basic - some of the differences include:
1) Handheld Contact is wireless, CompanionLink requires you to cradle sync - so you can get updates while you're on the road.
2) Activities scheduled on the device do not attach to contacts in CL
3) HHC can send 76 fields, CL has 4 custom fields
4) HHC will also record emails, phone calls and SMS sent from the device and sync them to ACT! history
5) HHC allows you to see other ACT! users' activities AND to schedule for them
6) HHC is centrally administered and supports OTA installs, CL requires it to be set up on each users' PC
7) HHC can support custom activities and histories in ACT!
There are other differences, but these are the main ones.
Regards,
Mike Lazarus
ACT! Evangelist
GL Computing, Aust