There are many items on the Known Issues support page for any given SU. Some are more likely to be encountered than others. I would be interested to get information from the community about bugs they ran into or features that they needed that really drove their decisions to upgrade. Lots of people out there are running on all different SU versions and our collective experiences might help highlight important gotchas or compelling new features. General overview of recent SUs: SU9 was out for a long time because SU10 (NPT) went through so much additional testing. There were more ESs and it was pretty stable. There was a freeze on new features for SU10 since it was a NPT, which meant there were lots of new features in SU11, which introduced a few bugs (new features are never completely perfect right out of the gate). SU12 came out fairly quickly after SU11 and some of the issue found in SU11 were never ESed in SU11, since they were found after SU12 came out. That brings us to SU13, which seems to have been a really solid SU that has been very stable. That's a bit of a general overview from my perspective. Specific Reasons to Upgrade that I would highlight: There were some significant performance optimizations in ESs for SU11 and SU12 including optimizations to some core subsystems like AdminServer, Notifier (QueueManager), EMS (multisite), etc. For customers with 2,000+ users in IA these optimizations are significant reasons to go to SU13. For customers with lots of handler activity (IPU has 1,000 threads / concurrent handler executions) there was a bug found in SU9 (fixed in an SU10 ES) that would be a compelling reason to upgrade if running on SU9. New features that should also be highlighted: Media Server new functionality is always pretty compelling and MS Faxing is no exception. Remote Content Server is another good feature for people with remote offices that want to slim down the amount of traffic that has to go between IC and the remote sites. Dynamic Attendant features were another really nice new feature that would be worth upgrading for. Also, the Interaction Web Portal is a significant new feature as well. What about the Web Administrator? What are your thoughts?