I am syncing my contacts/calendars via Google and everything seems to work fine, for the most part. The only things I've noticed that don't sync are birthdays and groups, but I have so few of both that doing it twice wasn't that big a deal for me.
On calendars, I have noticed that some of my event alarms don't sync to my phone, but sync just fine between iCal and Google Calendar.
I, too, want to find this. The effortless backup was one of the best things about the iPhone, and right now it's really the only thing I miss. I only had to use it twice in two years with the iPhone, but it's a nice safety blanket to have.
Capt. Obvious here, but just to be sure, go to the agenda view (or equivalent) and check settings to ensure that the desired calendar syncing between iCal and Google server is also set on your phone. It seems random - some updates, it seems to select all calendars, others, it doesn't.
If you're on 2.1 - ensure that under Accounts & sync, google account, that Calendars are checked.
If you're on 2.2, try a Sync all to get things lined up.
This thread may draw new Mac/iPhone to EVO lurkers, so with thanks in advance and not trying to hijack, here's my 2 cents on the transition from Apple, take these for what they're worth:
http://androidforums.com/reviews-evo-4g/130787-iphone-3g-user-who-switched-yes-friends-yet-another-iphone-user-review.html#post1214569
http://androidforums.com/htc-evo-4g/137396-likely-switching-iphone-evo-nyc.html#post1268569
http://androidforums.com/htc-evo-4g/118052-mac-root-all-evo.html#post1099333
On the latest issue of iTunes syncing, I don't have anything intelligent to add at this point.