The game is pretty huge and I think graphically it still looks pretty (except for the faces). The fun in the game lies in the side quests for some of the different "factions" and the ability to take things at your own pace.
As far as customization goes you can mess around with the way your character looks a lot, and every weapon/armor you equip changes the character model.
The main beef I have w/ this game is the level up system. In theory it's awesome but if you play w/ mixed tactics like a jack of all trades you'll find yourself over matched later on in the game.
The way it works is you have the usual attributes like strength, endurance, etc where you spend points once you level up. You level up by using skills . This is anything from simply moving and jumping to casting spells and using weapons. (I'll still maintain that becoming a "Master of Blunt" is the best thing I've ever done).
For example, you have a level progress bar that fills up a little each time one of your skills levels up. Say you do nothing but use heavy armor and swing a big axe. Each time you take a hit wearing that armor your heavy armor meter fills up a bit and when it fills up all the way once the level progress bar fills up. How many times you level up certain related skills, like heavy armor and blunt weapons, depends on how many attribute points you can add to strength, intelligence, etc.
So when you level up you can add points to three attributes, and if you don't use related skills you'll only get a few points, 2 or 3, when you need to get at least 4 or 5. Getting 4 or 5 means you used a lot of related skills wisely.
The problem I had is I liked sneaking, I liked using some heavy weapons, I used some magic, even some ranged attacks. So by using random stuff like that I'd only get 3s to level up. By the time I was level 30 I was getting punked big time by trolls and other baddies.
Thankfully this game has a pretty good difficulty slide bar, where you can adjust it so it "feels just right" and not too hard or easy.