We just upgraded our entire sales organization from Notes 6.5 to Notes 8.5.  We waited until there was a version of Connect for Lotus Notes that worked with this version of notes.  Users are experiencing severe performance issues in Notes when Connect is installed - delays opening email, flickering hour glass for extended periods of time, and overall slow performance.  When the connector is uninstalled performance improves significantly, so it seems that the plug in is the cause of the issues.  

Is this a known issue?  Is there a workaround?  A setting I should check?  SF tech support suggested uninstalling Lotus Notes (yeah, that's helpful) and could offer no further assistance.   I have very unhappy end users!