As a family we have Nook glowlights - never downloaded books from their store just buy epub from where ever is cheapest and sideload them.
There does a last seem to be a spread of prices for many ebooks.
Even without Calibre and DRM removal Adobe Digital Editions allows you to share ebooks betwen a limited number of devices.
I tried Kindles and Kobos and find the Nook easier to use.