I'm a long-time Apple user, so if you're not, take everything I say with a grain of salt
I didn't want to buy an iPhone (too expensive, and besides, everyone has one
) so I bought a HTC Tattoo instead. I haven't tested all the functionalities because my 3G phone package is not active yet, but I have some things to say already.
I was rather miffed that the only way I could synchronize my contacts with my MacBook was through my Google account. It didn't help that the app I downloaded to do this on the MacBook side is rather clunky and the French translation is awful, but that's just detail.
I can't generalize since this is the only Android device I've ever used so far, but the HTC Tattoo is obviously much easier to synchronize if you use Windows and Microsoft apps, and of course Google services. Don't know about Linux, but on a Mac it's far from perfect.
In the end it worked out OK for me. I don't need to synchronize my contacts (managed on the MacBook) very often, so it's no big deal if it's clunky. I do have a Google account and was considering making gmail my main email server, and I'm testing that solution now but so far it's working. Also, one good thing is that I was able to synchronize Google Agenda with my professional Outlook calendar very easily. So now I have my professional calendar on the Tattoo, and my personal one (which is almost empty anyway) on my Ipod Touch. So I'm not unhappy with this setup so far.
As I said, I can't test all the functionalities yet, the one I'm most interested about is Google Maps, but I'll only be able to make full use of it after my phone package gets upgraded, next week.