My PDA ownership has gone
Windows mobile >>> Nokia 9500 >>> Treo 650
I have to say that the treo is by far the most mac compatible.
The windows mobile pdas with the missing sync or with pocketmac, should work perfectly for syncing, the major problem is windows mobile software that only has .exe software that you're suppost to run with windows.
Sure you can get software to strip the windows mobile info out, but this won't work for every app, so some apps you'll want to use, but won't be able to install.
Nearly all palm software is a .prc file that can be installed onto the palm with no problem, making this nearly no problem.
I did the 9500 isync hack from osxhints (not sure about the other method that is mentioned in this thread.....sounds like it may be the same hack with an installer)
This isn't perfect either, as it messes with the MLSync info on the 9500, and causes issues backing up your nokia databases to a memory card in the future....