As nearly everyone says... They're fantastic, with a few caveats; never going to buy an e-cooking book, or travel guide - the lack of ability to skim through pages, or flick back and forth make this unworkable.
I've got a Paperwhite, 3rd, maybe 4th edition - love it. The backlight is comfortable to read in near-darkness without disturbing the otherhalf. I don't see the need for waterproofing, either don't read on a lilo in the sea/pool, or if reading in the bath, don't nod off.
I am an Amazon whore though - the individual convenience : global disaster ratio is too heavily skewed at good customer service (sorry...).