The latest generation, Kindle Paperwhite, Kindle Scribe 2, Kindle Scribe 1, and Kindle and the upcoming Kindle Colorsoft, all have something in common. When you plug them into USB into your PC or MAC, they no longer appear as external drives. This prevents users from using file managers to back up their books or to sideload new books onto the Kindle. Amazon has also removed the download and transfer via USB option for purchased ebooks from the content page. This will likely prevent people from striping the DRM from the books and sharing them on piracy websites. This is not
I’m in the same position as you. From what I gather you can still transfer files, I’m still buying a kobo when my voyage bites the dust.
As noted elsewhere in the thread, they do support MTP transport, so it’s definitely not as user-hostile as it first sounded. Things like Calibre will still work. However, the fact that Amazon also removed the ability to download ebooks in the browser for offline transfer suggests where things are heading. IIRC kobos have some anti features of their own, but I don’t recall the details. I wonder if something like the Daylight DC-1 could be even better. It’s not just a nice reader, but a proper computer. At least, if it actually exists.