Another update: I've been happy with iBooks on my Mac and iPhone, but still haven't managed to save up enough for an iPad, and my old Kindle is still in my drawer. I read a post from JFHey about using an Android emulator to install the Kindle Android app on my laptop, which would allow me to see my highlights and notes, and sync reading position. So I thought I'd give it a try. The short answer is, it's clunky, the text looks awful, and you can't copy/paste between Android and the laptop. But otherwise it does actually work! And it's free, and should work on PC and Mac. So that's something. I don't think I'll be using it, but in case someone might find it useful, here's what I did:
1. install Genymotion from
http://www.genymotion.com/
2. install Virtual Box from
https://www.virtualbox.org/wiki/Downloads
3. run Genymotion and install a virtual Android machine. At the moment Android 4.4 machines aren't working with Kindle, so use a 4.3 one instead. I used the "custom 10 inch tablet" one. Start it up.
4. download the "ARM Translation Installer" zip file from
http://forum.xda-developers.com/show....php?t=2528952
5. drag and drop the zip file onto the Android screen, it should "flash" (install) it. Then click the power button, close the window, and re-open the virtual device.
6. download "com.amazon.kindle" APK file from
http://apps.evozi.com/apk-downloader/ and drag and drop it onto the Android screen. (Alternatively you can install Google Play according to the guide above, and install the Kindle app that way).
7. run Kindle and sign up/in to Amazon. Tell Amazon to deliver your Personal Documents to your Android device.
8. read books.