Update 6/13/13: we added a known issue with transport rules to the blog post below. Today the Exchange CXP team released Update Rollup 1 for Exchange Server 2010 SP3 to the Download Center. ...
Updated Jul 01, 2019
Version 2.0
Blog Post
I am also waiting for a fix for the delegate Archive naming issue, so far I found what Ross Smith posted about this issue: "yes we did introduce a fix for E2010 SP3 RU2 that addresses the issue where delegate archive show the name of the primary mailbox owner. However, a client side fix is also required, but I don't have information on when that is shipping." (source: http://tinyurl.com/oftlvyf)
Besides that, I found this information that was given by an MS support employee on the phone: "Our Product groups have identified the code fix needed and the ETA is August 2013, to be specific Outlook August 2013 hotfixes will carry the fix." (source: http://tinyurl.com/mpqvnoh)
So I guess that would make it safe to install UR2 if you already have UR1 with the problem, but if you do not have the problem yet, but are affraid to get it by installing UR2 (like me) it would be best to wait for the Outlook update...