To summarise:
💶 Kobo will undercut Amazon Kindle pricing by 10%.
📖 You can download regular ePubs from them; you don't need to use a Kobo device or app.
🔓 DRM is trivial to strip.
🔃 Calibre will convert to any other format if you want to read on a Kindle, Palm Pilot, or whatever.
🧮 There is a loyalty point / discount scheme. But I'm not entirely sure it is worth it.