the syncing is totally software dependent, has nothing to do with htc really.
for me, vista syncing is beautiful. the new windows mobile device center works great at managing these devices.
the windows mail client in vista is a ****ty upgrade to outlook express. even calendar i think they just threw in to say there is one like OSX has.
although i agree it should be able to sync with win mail/calendar, i think very few people are looking to do that. these winmo phones are used probably mostly from people using outlook. its outlook mobile thats running the mail on the phone too. at work we've got some of these winmo phones and let them sync with exchange. it works perfectly. kept upto date with a mail/calendar/contacts live from the exchange server. any changes made on the phone/computer is sync'd right away.