I got the new Paperwhite 4 when they first became available. I already had a Paperwhite 3, which I liked a lot. I also have a Voyage with the flush screen and I liked the Voyage but I wasn't fond of the flush screen because I kept accidentally turning pages while reading. That almost kept me from getting the Paperwhite 4 but I decided to try it.
As it turns out I like the Paperwhite 4 more than either the Voyage or the Paperwhite 3. I haven't found myself turning pages by accident. I'm not sure why that's true with this thing and not with the Voyage. Maybe something to do with the different ways I hold them. But it's worked out very well.
My first Paperwhite 4 had a screen that wasn't quite as good as the screen on my Paperwhite 3 but was better than my Paperwhite 1. But that was only when they were side by side. The differences I see when comparing them disappear when I'm reading and they're all perfect.
My first Paperwhite 4 had 3G which automatically comes with 32 gig storage so if I wanted to I could have thousands of books on it. I normally keep only 20 to 40 books on a device but since it had so much room I decided to download a LOT of stuff to it and I did, but I find it more difficult to find what I want and I'm in the process of removing books now.
I liked the Paperwhite 4 so much that I got another one while it was still on sale, this one Wifi only. And when they went on sale again I got another one, also Wifi. Now they're on sale again and I keep trying to remind myself that it would be silly to get another one. I remind myself of that over and over. I don't know how much longer I can hold out. I may have to get one just so I can stop reminding myself.
I don't really care about it being waterproof, or I didn't till I got it. Now I'm finding that gives me a little peace of mind when it's in my jacket pocket and I get caught in the rain, which happens a lot recently.
My Wifi PW4's are both only 8 gig but that's still twice as much as my Paperwhite 3. Not that I need the room but it is something you mentioned.
By the way, the second two PW4's had screens every bit as good as my PW3 so the first one was just a fluke. There are a lot of individual differences in screens even within the same model. As you no doubt can guess, I have a lot of ereaders.
I also have a couple of Nooks and 3 Kobo's, although the Kobo's are older models. I don't really care much for the Kobo interface but it's okay and reading on them is a good experience. Just not my favorite. I have been thinking of getting a Kobo Clara HD but I haven't really decided yet.
My Nook Glowlight 3 has easily the best screen of any ereading device I have. Better contrast and a very even light. It's software is a bit buggy but it's usable. It doesn't have many features but it has the features I care most about. It's probably my second favorite after the Kindles. It also has 6 gig so it can hold a lot of books.
I live in a retirement home and I give away my readers when I stop using them and I've been thinking of getting rid of my older Kindles and just sticking with the Paperwhite 4's. I don't have anyone here wanting one now but as soon as I do I'll probably start doing that.
I don't concern myself with collections much. I have one for novels and one for short stories and one for misc. and that's it. And even those are mostly because I want to keep the home screen fairly clear. I think the best way to use an ereader is to read on it. There are better ways to store books.
[edit]I forgot to mention that I also dislike ads on my devices so as soon as my Kindles arrive I go to my devices page on Amazon and pay the $20 fee to have them removed. Actually I've ordered them without the ads for $20 more in the past. That option doesn't always seem to be available these days. But it takes 2 minutes to remove them when they get here.
Barry