Importing your stuff (contacts, calendars etc) is a breeze with the HTC Sync software, simply back up your iPhone to your computer with iTunes and then plug in your HTC and it does it all for you in about 10 minutes.
I'm pleased to hear you found HTC Sync Manager good. My experience with it was a nightmare, it kept crashing and I've given up on it. What desktop OS are you using?
Windows XP. It did lock up my phone twice, but that was probably due to trying too many things at once