They're both two different types of games, so I wouldn't even compare them. The Grand Theft Auto franchise is superior for what it is known for: gun-toting, gang-banging, car jacking hijinks and the Fable franchise is one of the more superior Action RPG's. I suppose the only comparison you could make is that they're both free-roam, but in that case I'd say I like exploring the GTA worlds more since you can use things like tanks, trucks, cars, helicopters, etc.