It adds a number of fixes and enhancements and I recommend it for all users.
Note: Apply this update to all machines that are involved in database synchronization to avoid issues surrounding renaming layouts, queries, and reports. This includes all machines that contain the Main Synchronization Database, Main Remote Database, and machines that have the ACT! Network or ACT! Internet Sync Services applied.
You might find the following knowledge base articles helpful:
- What Changes Were Made in ACT! by Sage 2010 SP1
- What Changes Were Made in ACT! by Sage Premium for Web 2010 SP1
- How to Download and Apply ACT! by Sage 2010 SP1
- How to Download and Apply the ACT! by Sage 2010 SP1 Hot Fix 1