I said 2GB of RAM, but honestly, my 6 runs like a dream with it's 1GB. I'd have really like the added image stabilization of the 6+ in my regular 6, but it's not such a big deal for me as I'm not a camera fiend.
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I would have liked non-rounded edges. IMHO they should have kept the basic style of the 5/5s. I think those non-rounded edges would have added more rigidity to the phones and the 6+ users could do with a little more rigidity. Maybe if the overall phone was more rigid they could have cut the bezel down more, or gone with an edge-to-edge screen design ala the Moto X. Bigger screen, smaller overall dimensions of the phones.