The bigger point is that studies really don't matter--I cringe saying that as an academic and a researcher!
In this case, all that matters is a person's own experience. If a person can read on LCD with not experiencing eye fatigue etc., then that's all that matters to them.
What screen is best for a person is a factor of what they need to do with the device and how THEIR eyes respond to different screen types.
So from that stand point there is no one "best" screen type for e-reading, and it's great that there are different options out there so everyone can find something that suits them.
I love my kindle, but eye strain has nothing to do with it. I very, very, seldom read for more than an hour a day, so it's a moot issue for me.