I would urge you to look at your usage pattern, and buy the device that makes sense. Personal example - I bought a Kindle DX a couple of years ago and am also an avid reader. However, my reading pattern changed drastically due to a newborn baby - could no longer read with the lights on, and free time became very limited.
My Kindle is now gathering dust, and I find myself reading on my phone and tablet the most. Phone most of the time because it is with me all the time, and I can read when I am say, waiting in a doctor's office or when travelling etc.
I really don't find it a pain to read on an active display (phone/tablet). And the Kindle app does a real nice job of keeping multiple devices in sync. So I can pick up reading on my tablet from where I left off on my phone.
But this is just my personal example. Your situation might be very different. Personally, I really like Kindle Paperwhite for the backlighting, but Kindle is more of a walled garden than a Kobo.