Ohh... I feel like this is such a loaded question.
I read GoT over the summer specifically because I wanted to watch the HBO series but knew I had to read the book first.
Three months later, I got through it. In no real order, here are my thoughts:
1. Maybe it was due to the number of characters and settings he had to introduce, but I didn't feel like I actually got into the story until at least 1/2 way through. That seemed like a big ask of your readers, to hang on for 400-ish pages.
2. Yes, the world building and character development were all amazing. Thankfully, there were maps. I referred to them every time I read. Along with the house information at the back. I needed all the supplemental material.
3. Yes, Martin makes his characters go through hell. Yes, some get their just desserts.
4. I finished GoT curious to know what happens next, but not "OMG I have to buy the next book right now!" curious.
When I finished GoT, I took a much-needed break and then NaNo began. I'm still toying with the idea of reading the 2nd book, but the general consensus I've heard is that book 2 is a bit tedious, but everything really picks up in book 3. I'm not sure if I'm willing to give another 3 months of my life for a 2nd book in hopes of caring enough to read the 3rd.
For now, I'm glad I read GoT. I love fantasy and really enjoyed the story. Yet even as I type this, I feel wholly indifferent, like I'm trying to come up with great things to say. I feel like as a fantasy writer and lover, I should try book 2. Maybe in January when there's nothing to do in MN but stay indoors.