I was quite happy with Missing Sync f. Windows Mobile (MSWM) 3 under Tiger.

However, updating to Leopard required also an update to MSWM 4, but even the latest version (4.0.3) does not work at all, even in the most straightforward circumstance. The USB connection just never gets established. So I do not even get that far that I could start a sync. I seem not be the only one to whom this happens. Unfortunately there is no other software out there that can sync Windows Mobile 5 with a Mac - but MSWM is too unreliable to use it. If it fails even in the most simple circumstances, then the quality assurance must be really lousy. Syncing is usually required for data which are important and precious - therefore the level of quality and support provided by MSWM 4 is completely unacceptable.