I'm looking forward to seeing how these devices play in real world usage. The two things that jump out at me immediately. 1. Most important: On a device with a small screen pixels should be precious. It worries me that many of the built in apps use a significant and unchanging amount of the screen to tell you what app you are in. I don't know if it will really impact usability, maybe there is enough screen real estat…
To use Windows Mobile, you had to deal with ActiveSync. To use ActiveSync, you have to be fairly tolerant and technically proficient. For example, when upgrading the OS, you have the responsibility(1) of manually backing up all your contacts, data, apps.
Contrast this with iTunes (yes, iTunes isn't elegant) - when iOS 4 came out - it downloaded it and asked if you wanted to upgrade your phone and did so without losing settings, data, apps. Now, Android supposedly can do OTA updates. The point here is if WinMo7 requires ActiveSync - it is severely behind the times.
I'm hoping WinMo7 won't require a user to use ActiveSync and it is all stored securely in the Windows Live cloud. I usually used lots of colorful adjectives when dealing with ActiveSync. I had a boss who was convinced to get a WinMo device by a co-worker; she lasted only about a month (ActiveSync).
(1) http://www.htc.com/www/supportdownload.aspx?p_id=59&cat=...