As expected, some will love it, some will hate it Fantasy... Is there a more difficult genre for TV? It is so hard to make a great show, and so very easy to completely ruin it. Experience has taught fans to be cautious as they've dealt with countless disappointments. It also skews opinion for the general audience (whatever that means, I rarely generalize), yet, I believe it somehow does.
So, you've been hyped? We all were, which intensifies all positives and negatives. I won't praise it too much, other reviews do that quite well (and not quite so well). Here I'll try to address the people who haven't seen the show and are trying to decide whether to watch it, or have seen some but are still undecided whether to keep watching. Therefore I look at what turned most people away (from what I've read so far).
The confusion. There are many characters in A Song of Ice and Fire and really no easy way to introduce them on screen. They all play a significant role and although things will be omitted, it will still be... epic. The first episodes will be the most difficult to follow. HBO know this and are trying to relieve the problem with various features and guides. Go check them out if you were frustrated by the scope of the show. It really has to be given a chance, at least several episodes, in order for it to work.
The sex and violence. There is a lot of sex and violence, I agree. But is it really that much different from other shows by networks unconstrained by ratings? Boardwalk Empire, True Blood, The Tudors, and so on and so on. Would it be a different story if this wasn't fantasy? Perhaps. Have in mind that all of this is much more prominent in the books (without being anywhere near a theme), it's not thrown for the sake of it, and it serves a purpose - to build the characters.
The plot. Someone said predictable? This is one of the most unpredictable stories ever told. It's big and complex and it goes to places you'd never expect. Or wish. It's not history, so there are no moments like "Anne Boleyn? I know how this one ends... Just a matter of time." It's not fairy-tale like Lord of the Rings where the good guys ride dragons and eventually defeat the bad guys. There it all comes down to how exactly the bad guy will be killed and how many fictitious extraordinary places we'll visit before it happens. Eragon is predictable. A Song of Ice and Fire is shocking, surprising and very, very addictive. Game of Thrones therefore has a huge potential to be just like that. If you are willing to let it do it's magic.
Why the hype? Surely some will be disappointed due to it. But the reality is, because of the genre (and the series is not quite what is expected of the genre), HBO needed to bring in as many people as possible and hope that enough of them will go the distance of several episodes I'd assume are needed to achieve the "crack on paper" effect of the source material. So, don't feel cheated. It was expected that some (perhaps many) viewers will not understand and like it.
Last point. It is not fair to judge an entire show from a single pilot. I'm sure halfway through the season those who watched without being too involved will not regret it. Those who changed the channel will miss a great fantasy story, and well told at that.