You'll play it for ages and then you'll get bored of it. Months later you'll play it again and again.
You'll start of the first time not knowing what to expect, you'll work your way through dark, dingy caves and then find yourself outside - you will be gobsmacked. Outside you can see across land to distant cities and its beautiful, the graphics are amazing. However that depends on the weather in the game. If its sunny and bright you can see far far away into the distance, but if its raining and foggy its depressing.
The combat is very fun but the leveling up isn't very good. As you level up, new, harder creature amazingly start poping up around the land. Thats very annoying because you can't be the most powerful, dominant person in the game because they keep up with you.
The quests the first time you play, you will really love. You don't know what to expect but when you replay the game you do, and they a not as enjoyable. So mods are a really good way of making the game more interesting because they keep on adding new things to do.
Get this game. But I strongly advise you too relax when playing it. Walk, run or ride everywhere - don't speed travel. It ruins the feel of the game.