What I miss from the world of blackberry:
- multiple profiles and levels of alerts, ringers, and repeating tones... Blackberry excels at this
- mark all messages as read. Is that really such a hard thing to implement?
- cool themes
What I like about the IPhone:
- great apps and app installation. That is in stark contrast to the blackberry appworld experience. Also, all devices on the same iTunes account benefits from a purchase! Now that's value.
- great user interface
- syncing and backups are nearly foolproof! So different from the blackberry desktop manager...
- great photo apps and social apps!
Overall, I would say that my experience on the iPhone 4 has been a very positive one, quite different from my experience with the iPhone a couple of years ago.
My other phones are coming to the end of their contracts and while I'm fine with an android phone, the idea that I can reuse the apps I've already purchased for the iPhone and iPad is a big influencing point on whether my next device will be an iOS device or not... There is definitely an overlap of apps, but the need to buy those apps again is a bit of a blocker to going with a non-iOS device...