Android to iPhone -- Your Experience

So the opposite of this was posted in Android Army yesterday but I'm interested in hearing from people who switched from a HIGH END Android devise to an iPhone. Please no " I had a G1 for 4 years and it sucked", stick to phones that are/were higher end.

What did you have and what did you switch to?
Why did you switch?
What do you miss?

What is the biggest difference you notice?

Which phone is better?