Gamespot has this game underrated. A must play for any Action/RPG fan.
The most similar game(s) I can compare Reckoning to are the Fable series, specifically the later fable games which had more of an open environment feel. The artwork is high fantasy and the zones, while interconnected without loading screens, are still segregated in that there are narrow corridors connecting them. The only areas requiring loading screens are when you enter buildings, caves, etc.
The best thing about this game is the combat, which feels very action like, and again, at least to me, similar to Fable, only better and more advanced. The character development RPG aspect also seems pretty good.
The main area I disagree (at least so far) with Gamespot on are the quests. I have barely seen any "go kill 10 of X" quests yet. In-fact, not only have I found the quests to be interesting and each having their own stories, each has it's own voiced over dialogue and the dialogue work in this game seems to be some of the best I've ever seen!
Bottom line:
Excellent combat.
Excellent voice-over work.
Interesting quests (from what I've seen).
Good character development.
Good character customization.
Good visuals.
= A Very Good game.
Take Fable 2, add more character customization and RPG elements, make the combat cooler, add in some of the most detailed voice-over work ever seen in an xbox game, and the result is pretty much Kindoms of Amalur: Reckoning.