I would say that this game is made for a very specific audience. For one thing, it was created by a rather small studio. It's not Bethesda or BioWare, so don't be expect something in the leagues of Skyrim or Dragon Age. However, it is still a game you should definitely try if 1) you love the ASOIAF series (or the show), and 2) love RPGs. If you're not a huge fan of either, you are likely to be very disappointed. Being a die-hard fan of anything ASOIAF and awesome RPGs, I knew I had to get this, regardless of the reviews.
GRAPHICS - the graphics are more like for the PS2 or XBox. It's definitely nothing to write home about. It's a little dark and blocky, but change your television/game settings for a more enjoyable experience. Okay, so the graphics are not so good. Don't play this for the stellar graphics.
DIALOGUE - the dialogue actually isn't that bad. You get the real acting voices of Cersei, Varys, and Jeor Mormont, which is pretty awesome. It's definitely dialogue-intensive like a lot of RPGs, but that shouldn't bother you if you're playing an RPG. You also get to make decisions based on your own dialogue that make lasting impressions in the game. I think a big complaint here is the lack of witty humor in a dark setting like a lot of RPGs have (Dragon Age, Skyrim, KOTOR, etc.)
BUGS - this is my main issue with the game. The bugs are bad. My game froze up twice at the beginning and had to re-create my character. I was about ready to hurl the game out the window after that. No one likes to spend $60 on a game and then have it freeze up. This game doesn't autosave all of the time like some of the newer games, so make sure you save a lot.
GAMEPLAY - the battle system is similar to Dragon Age, but a lot more button mashing. It's not terrible. I like that they have a perks/flaws system, where you have to balance the two. Want an awesome perk? Well, you have to pay for it.
PLOT - things are a little murky here. There are some things that characters (like Cersei) do that are really out-of-character and seem like plot holes. I've heard from professional reviews that the ending is really great, so once I finish it I'll make an update here (I'm like 60% through). Is it non-linear? No, not really. You definitely won't be traveling to Saltpans and taking a ship to Braavos (wouldn't that be nice?).
I would like to add that regardless of storyline perfection (how can it be perfect, anyway? - it's not canon), the developers of this game are TRUE fans. They have been working on this game since before the inception of the television show and know their stuff. If you get the art book with it and read it, you'll know what I mean. They are ASOIAF-smart. The reason that this game is not absolutely 100% awesome is because of budget constraints/small studio, not because they were some kind of hack developers that wanted to make a quick buck off of a Game of Thrones game as quick as possible. Trust me, these people know their stuff.
Overall, I recommend this game for those who are ASOIAF-crazed, love RPGs, and aren't expecting a Skyrim clone turned into Westeros. You won't find that here. But you'll still have a fun time exploring Westeros.