I stumbled across this tool on my iPad on the Apple Apps Store. I used it to help diagnose why my iPad would not correctly sync with and Exchange 2010 server that I had deployed. The Microsoft tools said it was all working fine, but this tool helped me understand that there are in fact differences in the way the Apple iPhones/iPads perform ActiveSync vs the way that Windows devices do.
Note that there are both Windows versions of this tool and the Apple version – both work well.
You can download the tool here