Choosing between Walmart/Kobo and Amazon (and Apple for that matter) for a digital ecosystem is about the lesser of two evils. I’ve being moving away from DRM content over the past year for my library — either by buying non-DRM content or removing it. It rarely is cheaper, but it continues to approach Amazon prices lately.
I really want to switch away from Kindle devices for my next eBook reader. The Kobo’s look solid, and support regular ePub’s as far as I know.
For audiobooks, I cancelled my Audible subscription last year and have been winding down my backlog. But for new audiobooks I’ve gone to Downpour, and their non-DRM system works great.