As a birthday present from Camilla, I have an new kindle Oasis, upgrading my very basic kindle from six years ago. The Oasis is expensive, but is the only current model that has physical page turn buttons. And so far it's clearly better than the old kindle, except for one really annoying software regression.
The back-light is great. It means I can read in the dark while going to bed myself, or while trying to get Helen to sleep. I had been using a smartphone for the latter, but that's pretty terrible for reading from.
The larger and higher resolution display (17.5cm up from 15cm and 300dpi up from 167dpi) is nice. It makes everything just a bit crisper, and some full-page PDFs are now readable without zooming. (Annoyingly, while the screen auto-rotates by 180 degrees, it won't auto-rotate by 90 degrees but requires five taps to switch between portrait and landscape modes - and it doesn't remember that choice for individual books. This was the same in the old kindle, but I was hoping that in six years they might have added the obvious functionality here.)
The touch-screen makes dictionary lookups (when reading German) much faster. Unfortunately with the new interface there seems to be no way to look up a word inside a dictionary definition, which is annoying because I'm using a Duden German dictionary rather than a German-English dictionary and definitions like "Sturheit, die: das Sturstein" would be more useful if I could easily look up "Sturstein".
The one really annoying regression is that there's no longer any way to create "collections" on the kindle from calibre, the ebook management software I use. The only way to do this now is to create them manually on the kindle and then laboriously classify all my books by hand - which I'm just not going to do. I thought I could jailbreak the kindle and get the calibre collections functionality back, but it turns out that was two years ago and there is no jailbreak for the current kindle firmware. *sniff*.
Addendum: the Oasis battery doesn't seem to last as long, but that is presumably because the light uses more power. Countering that, charging is really fast now, where it seemed to take forever on the old kindle.