I love my Sony350 but the thought of being tied to the Sony Store does not thrill me. So wifi for my sony is not a must. I would actually prefer being tied to the Amazon store. So I like my Kindle for that. If Amazon comes out with a Kindle touch screen I will be tempted to get it.
Still I'm waiting to see what Amazon & Sony come out with this fall. And to be honest since both of my e-readers work fine I can't honestly say one is better than the other. The only thing that puts the Sony in the forefront for me is the touch screen, size & the ease of using the dictionary, oh & the bookmarking & the adding to collections (though I admit I prefer the collapsible collections on the Kindle & that they are not left on the home screen as well as in the collections). All these I prefer on my Sony.
I think I'm getting long winded.
But as for the way I use my readers, I can't say one is superior to the other. I don't understand the hardware claims, nor the software claims. I just use what I have & it works for me. But then I'm not into tinkering with any of my gadgets.