Hey, I've read them. Although I didn't really much like the fourth one, the first two were excellent!
When I first picked up Hyperion, I had to put it down because the first 30 or so pages were difficult to get into, but then I went back to it and was amazed at Simmons' literary skill. Doesn't he use a lot of the same style as Keats? I'm pretty sure that Keats has a poem or something called Hyperion, in fact.
Suffice to say, good read indeed!
Thanks!
prag