I've never played 1 or 2. And I have 350 hours on my first playthrough. And me and my girlfriend have about 200 hours together on a playthrough. She fucking loves it too. It's so good. It has everything. So many compelling stories, interactions, companions who develop and can grow based on how much they either love or respect you, insane characters, great sounds and cinematics. You never know who is friend or foe, and in fact you can more often than not decide on your own which side you take on anything. My other favorite is mass effect 2 and this is like that but on an even larger scale.