Kobo store is convenient but feels pricey sometimes (I don't have experience with the Kindle store). I don't mind paying them though, because it's still easy enough to strip the DRM and make backup copies of my books. If that changes, I'll take my business elsewhere.

I make a lot of use of my local library through the native Overdrive integration.

There's nothing wrong with the Kobo store itself, but some titles are only published via Amazon. Especially from self-published authors or participants in Kindle Unlimited. Whereas the major releases from the bigger publishers are usually widely available.

This is somewhat annoying. Please don't offer only one storefront as a place to buy your work.