Purchased mine via Kobo.
http://imgur.com/a/xmCjOI usually read my books on the phone, the above screenshot is on my PC. I have a portrait monitor for coding but it also comes in handy for reading.
I had to repurchase the books for my reread last June as I originally had the books up until TWLW on my Kindle, but forgot my login. I had a few years of little to no books read due to going full blown workaholic around 2012.
Somewhat annoyed about the cover of TDTCB being different, but I got that before changing shop regions. Also I have no idea why TJE's cover is all blurry like that.
And yeah, I'm mostly an ebook as it's quicker to get the books as well as an issue with availability in this country.