Installation of this CU caused approx half of our Win7/Outlook 2010 clients (Office Pro Plus 2010 SP2) and our only Win 8.1/Outlook 2013 client to have connectivity issues to the Exchange server (client hangs, unable to view email in preview, unable to open email, unable to delete email, "Cannot start reminder service" error, etc.). Rolling back the update resolved the issue. Similar symptoms and resolution discussed at:
http://www.edugeek.net/forums/enterprise-software/146585-outlook-client-issues-following-exchange-2010-rollup-8-a.html

In addition to the above symptoms, the RPC CA logs had large numbers of entries on affected users of the type:
2014-12-10T12:02:32.052Z,50,188,/o=xxxx/ou=xxxxxx Group/cn=Recipients/cn=xxxxx,,OUTLOOK.EXE,14.0.7108.5000,Classic,,,ncacn_ip_tcp,,,fault,00:00:00,,Watson: [IndexOutOfRangeException] Index was outside the bounds of the array.

We are also experiencing an issue with this update. Rolling back to 7...

Technet forum thread:
https://social.technet.microsoft.com/Forums/en-US/1be9b816-b0ab-40ea-a43a-446239f8eae3/outlook-client-issues-following-exchange-2010-rollup-8?forum=exchange2010

I love you. Thanks for putting this out there. Definitely helped.

The Microsoft Exchange RPC Client Access service terminated unexpectedly. It has done this 1 time(s). The following corrective action will be taken in 5000 milliseconds: Restart the service.

Over and Over all day long...client connections have had issues.
microsoft.exchange.rpcclientaccess.service.exe
The Microsoft Exchange RPC Client Access service terminated unexpectedly. It has done this 1 time(s). The following corrective action will be taken in 5000 milliseconds: Restart the service.

Did rolling back to 7 resolve the issue for anyone?

In no way should you install this update, I have never seen so many issues with Outlook 2010 as this update creates. Outlook will produce random folder locking issue, deleting email issues, and several other issues. Messages like Cannot open this item and Cannot open this folder, Cannot expand the folder, Cannot display the folder. Microsoft Outlook cannot access the specific folder location. These are examples of what you will see and triggered when new email comes into your inbox. The messages will appear from different email being opened and different folders within Outlook. Random folder and message issues.