I've read a couple of books on an iPad (most recently Shogun, which is >1000 pages, and several smaller novels). I've also had an extended play with a Kindle. The Kindle is kinder on the eyes, but not to the point where it makes a practical difference to me.
I think people might look at a laptop display and from there decide that LCDs are awful for reading from (this was my opinion). But the iPad is a significantly better reading device than, say, a laptop, because you get much more control over where the display goes in relation to your face. This sounds like an obvious thing to say but it does seem to make a big difference.
To relate back to your reading experience: I was reading Shogun in 2-hour sessions (or longer) and didn't notice any eyestrain.
I think people might look at a laptop display and from there decide that LCDs are awful for reading from (this was my opinion). But the iPad is a significantly better reading device than, say, a laptop, because you get much more control over where the display goes in relation to your face. This sounds like an obvious thing to say but it does seem to make a big difference.
To relate back to your reading experience: I was reading Shogun in 2-hour sessions (or longer) and didn't notice any eyestrain.