Part of the reason I went with a kobo over the kindle is that they support ePubs. The kindle honestly seemed a bit nicer hardware wise but I like the ability to build and read my library of DRM free books well into the future. No complaints about the kobo so far and it's lasted me nearly a decade by this point. Once it finally kicks the bucket I'll definitely stick with them.
If you have a kobo, I highly recommend checking out koreader[1], which is an open-source ebook reader and is highly configurable (to the point where you can even write custom css rules from withing the e-reader), integrates with calibre natively (you can even connect to your Calibre library over Wifi), has a solid support for CBZ (with features like auto-cropping the border around your comic, automatically or manually), and more.
Having used it, I don't think I could go back to Kobo's reader (and even less to Amazon's, which is a joke in term of configuration options).