I currently have a iPhone and a Nexus 7. The Nexus 7 has shown me Android is a very capable and mature OS so I might be replacing the iPhone with a Nexus 4. But having said that I do like iOS so tempted to get a iPad mini with retina (whenever it shows) for the tablet. However I think as devices like the Nexus 7 and 10 get into more dev's hands we will see more tablet optimised apps for Android, the number is already starting to increase a lot.
However I do have a MBA which is very portable and capable device so even a "big phone" could eliminated a tablet for me.
Galaxy SIII for phone.
Nexus 7 for e reader.
IPad for full tablet, gaming, etc.
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Stay with the iPad.
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People are getting around 5 hours of screen time battery life on the Nexus 10. Kinda sucks, but I guess that's what happens when you're running that many pixels.
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I really want a mini. Don't really care about the Retina display crap.
Man android as a tablet is kinda boring especially when I have my Apple TV and like to do mirror. Android as a phone is cool but when most of my friends are using iMessage it's handy to respond either with my phone/ipad/mbp.
So many tough decisions to weigh