I'm a bit late to this discussion, but I've tried a few e-readers, so I'll have at it. I had a Kindle, 2nd generation, for years, which I had a love/hate relationship with. Reading a single book off it was great (or so I thought at the time); however, the directory structure (or lack of) and the lack of microSD expansion slot was enraging (both were deliberate marketing -> design choices, as other companies had made these standard). I basically had to load on a few books at a time, to keep some semblance of order, which meant being tethered to my PC. The meta-data was quirky, and the dictionary slow and uninspired. I did like the hard page turn buttons, unlike the later versions.
I finally broke down and purchased a large format reader, the PocketBook Pro 912, so I could read PDF's and textbooks. I owned it for two days, then resold it. It was sluggish (read: so slow I often wondered if the device had stopped working), quirky and a real hassle to use.
My last stop was the Nook Glow, rooted to Android. While it's not perfect, it's the closest to perfect that I have found. I can now read any format- any. I have the desired directory structure, and the space to hold my entire collection. The dictionary is superior to the Kindle, and is a different Universe from the PocketBook. I even have an app that lets me drag large format PDF's around like a tablet, with no refreshing, letting me read Textbooks, Magazines and such (not ideal, but usable). The font options are generous, and the zooming is easy and useful. If I can't get a book to "feel right", i just pop over to Android and use one of the many other e-book readers that I have installed. The option for hard and soft page turns is nice, and it even lets you play with the keybinding. And the glow light makes reading in bed ideal.
Now, had I not rooted the Nook, I might still like it, but, without the added versatility I now have, it wouldn't be nearly "cure-all" that it is.