My agency rolled out Office 2007 last quarter and generally the results were favorable. An exception was the performance of Excel. Several of our heavy users experienced serious performance issue when each tried to use worksheets that
operated fine in Excel 2000 (we skipped 2003). SP1 has resolved all our known performance issues. The attached graph demostrates some of our findings. I highly reccomend that anyone deploying Office 2007 due so with SP1.