I was annoyed at having a new character introduced at first (the fanservice prostitute a distracting introduction as I didn't remember her from the books, with good reason) but now I see the point: often the books depicts a character's point of view and his thoughts. Outside having that character narrate everything he, or she, is thinking (which doesn't make great television) you don't have many options. Introducing new characters with which they interact instead, and that explain the same plotpoints (thus staying true to the story and preventing plotholes by having main characters share important plotpoints which make later decisions stupid) is a neat solution as long as they remain secondary characters. So far so good.
As with a lot of HBO shows, they seem to love blurring tvshows with porn and I can't see myself recommending the show to anyone outside my age range. Even the Sopranos were never this explicit, they'll probably outdo trueblood soon at the rate they're going. But if the porn keeps the show on the air then it's a small price to pay. (porn is cheap, special effects are not, same reason I forgive not seeing the direwolves all the time)
Casting wise for the main characters are all very good with a few exceptions.
Tywin Lannister didn't do it for me (I expected John Glover) but it's only been a first impression. He might be decent. Catelyn Stark is ok but not great, the actress that plays Cersei manages to be more sympathetic than her so far. Jon Snow sounds really whiny but that's also in the role so I might just dislike the character. <<The Mountain>> is pretty hammy but I'm not sure that can be avoided. He has the physique though. Finally the king is not very impressive either.
Now on a good note. Everybody else is very good. The child actors are especially promising and Tyrion's actor steals every scene he's in. You should also note every character that didn't seem as good as the others are relatively minor roles.
Finally the editing is very comprehensible, the story even seems simpler to understand as opposed to the books and the pacing of the story means we should have enough material for the next decade. Hopefully the next book will be out by then.