Well, I got an iPad Air a week ago. I'm really enjoying the lighter weight and faster processor. I found a case I like on Amazon that doesn't add much weight. I drop the iPad + case into a Brenthaven ProStyle sleeve when not in use. Mostly because of Accordance, I went to the 64G model. I am a very happy customer.
It was Dan's comment regarding reading a PDF on an full-sized iPad that really tipped the scales for me. In landscape mode I am able to read the full width without fiddling with it. I would not be able to do that on a smaller device. Since that is function that matters to me, I spent the extra $100 and am carrying a larger device.
My husband gave his old iPad 3 to our daughter, who took her iPad 2 to Target for $200 card toward a new iPad. She has mailed us the card which my husband will use toward a new iPad Air. He is actually planning to go to Target on Thanksgiving, risking life & limb, to buy the iPad he wants and to get the Black Friday $100 gift card with his purchase. That's assuming they have the 64G Wifi that he wants. I'm not leaving the house! Meanwhile, he's using my old one which we will sell on eBay when he gets the new one. The pink Smart Cover doesn't seem to be bothering him much.