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iOS 6 is really fast on my iPhone 4. If I see an iPhone 5 in action, it might change my mind, but I've never really compared about the speed of my iPhone 4. In fact, I wouldn't mind keeping it, but since my contract is over and I need to sign to get a better monthly fee, I'm going to get the 5.
 
I was reviewing the iOS 6 features list and was surprised of all the features that are only on 4s and 5. I recommend you read it. I think maps with GPS navigation was one of them that was missing and I love the app.

Maps, still has directions. It's just the spoken turn by turn feature that is missing. You can get third party apps for this and you'd still be saving money over the 4s / 5.
 
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