I've gotten used to the black/white flash refresh on eInk and I'm fine with reading on LCDs so the tired eyes doesn't really apply to me. The inability to read in the dark with the Kindle is slightly annoying but it just means I have to turn a light on. Its probably better for your eyes to do so anyway
What I do like about the Kindle is that it is very light, has a very good battery life and comes with 3G support. The battery life is the main aspect as I like the ability of not really worrying about the Kindle except to just plug it in every 2-3 weeks to top it off.
It really comes down to what you want out of your eReader.