Prompted by "OneNote (included in most versions of Office 2007 and 2010) is good" in the last Windows Secrets Newsletter: I found MODI - Microsoft Office Document Imaging - in Office 2007 quite outstanding. I recently upgraded to Office 2010 which no longer includes MODI but provides One Note to do the OCR work.

One Note's OCR is very substandard indeed, nowhere near as good as the old Microsoft Office Document Imaging. The only good news is that I could install just the MODI from Office 2007 alongside my Office 2010 installation and use it for my OCR requirements. Very clunky to do all the steps but great OCR performance.

Tests on all sorts of sources including scans and pdf files show many more mistakes in One Note than MODI. I raised this with a Microsoft support person who confirmed my comparative results and said he would pass it to the software developers.