It's Fable meats Dragon Age.
World exploration - it consists of several connected sandboxes, each of which kept me occupied for many hours. The world reminds me of Dragon Age 1, only much bigger. There are a lot of quests to complete (main, side, factions). But there aren't many non-quest activities, like stop at an inn to play cards or throw dice...
Story - non-existent. After the first several dialogues which were boring at best (not to mention the blank look of my character), I started skipping everything. I only hit the dialogue option that gives me a quest. This is not necessarily a big problem. Remember the countless hours you spent button-mashing in Diablo, which had a generic story and characters at best...
Fight system - best thing about the game. Killing monsters is fun! After clearing an area and leaving it, the game re-populates it with monsters. So I would go back just to fight them again cuz it's fun.
New weapons look and feel different from old ones. It's actually fun to explore for weapons and armor, compare stats, or find matching sets. Weapons/armor can also be upgraded with gems.
Loot system is also alot of fun. The game has a junk system which actually makes sense and works well (unlike the nonsense junk system in Dragon Age 2 which was a junk game). When you find a new item you can compare it's stats to the currently equipped item. Then you can decide to equip it, take it, or add it to the junk. There are nice keyboard shortcuts which are very convenient (1 - take, 2 - compare, 3 - add to junk). All the junk is then easily sold to a merchant with a click of a button. Collecting money is worth it - there's much to buy at the stores.
The game has a few shortcomings, such as personal inventory and store inventory cannot be sorted (e.g. by name, cost, etc). This is a must for any loot based rpg. The Witcher had similar problems with the inventory.
Also the physical platform on which the character moves is too picky and restrictive. E.g. you can only jump down to a lower level at a predetermined spot that's shown on the map. Sometimes you have to walk around for a while to get to a place that you can literally almost touch from a different spot. Obviously there is no jumping in the game. After all it's not a free-roaming rpg like Skyrim where you can jump your way anywhere. But at the same time it is much better than games like Dragon Age where you follow a single narrow path.
I recommend.
Update: After playing several more times and trying all 3 classes at max level, things get repetitive and the game fails to keep me interested. The above review is mostly based on first impressions, but as time goes it feels more shallow and disengaging. The lack of a meaningful story and characters is a big turn off. I don't think I can finish it, least of all play it ever again. Zero replay value.
My standard for a good rpg is Skyrim, even though that's more of a 1st person action rpg. Even after completing all the quests in Skyrim, I kept coming back to it because of the pretty world, engaging fights, great leveling system, and platform physics which allow you to jump your way to almost any location. Kingdoms of Amalur on the other hand is one of those overly scripted (DA:O) single-play, forgettable rpgs that fail to keep you immersed.