Yep, there's no wrong answer here as everyone has different eyes different reading habits.
I don't doubt that reading on LCDs with the proper brightness probably does lead to more eye fatigue than reading e-ink under the proper lighting conditions. And the battery life of e-ink devices is second to none. So I see their appeal, and I do really like my Kindle.
But at the same time, for me personally, I'm not an avid reader. I seldom read for more than 60 minutes a day--discounting work related reading which is all on the PC or printouts currently (Kindle sucks for PDFs, A4 sized documents etc.). So the eyestrain issue is pretty moot. I could read on my laptop with the brightness up for an hour with no real eye issues--the form factor just sucks. Battery life isn't much of an issue for me either, I have no problem plugging in every night or two. If something can get 8-10+ hours so I can get through even a heavy day of use I'm fine with it.
So it's very much, as I've said many times, really just a matter of individual preference and finding the device that works best for you. I like my Kindle, but I won't buy another e-ink device as I don't really read enough to need it and something like the iPad that does more than reading, can handle PDFs, newspapers, magazines, comics etc. fits my needs more.
While the person who reads straight text constantly for hours on end will probably be better suited with an e-ink or other reflective screen in their devices.