* Works in lots and lots of countries
* Great iOS and Android apps to supplement reading on Eink
* Well-priced devices, even if you pay to remove ads, that offer years and years of software support and are extremely durable/reliable
* Great hacking community and ability to use things like DeDRM to bring your purchases to other devices
* Insanely robust library that is far more consistent than other services.
* Ability to easily side-load other content via the Send to Kindle feature
* Audible integration/sync/discounts
If you prefer Kobo, that’s fine. But I’ve always seen it as the second-rate alternative owned by the second-rate Amazon (Rakuten). If I’m going to get tied into any ecosystem, I’d prefer for it to be the biggest/most active. But that’s just me.
Edit: formatting