I didn't care for the game at first. I actually considered quitting after the first few hours. But, since it got such good reviews everywhere, I decided to power through, in hopes that it would pull me in at some point. And, it really did pull me in. I've now played every side quest that I've come across, and figure I'm getting close to the end. I'm really glad that I kept playing. It is great.
With that said, I can't put it in the G.O.A.T., or even greatest of the generation conversation. Its a half-step below that level, IMO.
Then again, as I haven't finished it yet, maybe my opinion will change.