The only issue {besides some crashes related possibly to graphics update} that I found for Excel with the update was:
All hyperlinks were removed. This caused Excel to report a Data Loss message to me whenever I opened a workbook. If you save the workbook it will save without the Hyperlinks {in my case}. Only solution I found was basically, I had to rebuild all my Hyperlinks, which was very tedious...
I reported this to the Mactopia forums, and someone from Microsoft is looking into it. The issue is not hyperlinks not working, but rather, with the update, all hyperlinks disappeared. Specifically for me, any workbooks with hyperlinks in them, that were created in Office 2k3, 2k7 obviously on PC's are my problem.
Anything I created in 2008 and opened after update, seem to be ok so far. Still testing, as I also had to remove my Leopard Graphics Update 1.0 to address {hopefully} an issue where my MBP would lock up completly due to some actions done with Excel.
So far after removing the graphics update, I have not had an issue with crashes or lock-ups, but I am still testing.