[Sirtel]

While I don't have a Clara, I can answer some of your questions about the Kobo software in general. For information, I used Kindles for a decade before fully switching to Kobos.

- Kobos are significantly better than Kindles in some areas (integration with calibre, customizability, hackability - no jailbreak required at all, and it's possible to downgrade the firmware version if you happen to dislike an update); but also a bit worse in others - no syncing sideloaded books between different devices and apps, for example

- I have no complaints whatsoever about the build quality of the 3 Kobos I've owned

- the software is a lot more open and customizable than that of Kindles. Older models could be somewhat laggy, but maybe the Clara BW is not. Someone who uses the Clara must answer that.

- Kobo devices display book covers as screensavers, but you can use custom screensavers if you want. I use my own images, for example, as I don't like book covers either

- no ads other than book recommendations on the homepage, which can be disabled with a patch or by enabling the sideloaded mode (the latter loses the homescreen entirely, so that the book library page becomes the new homepage)