I dare say there's more content in GTA Online and if you're afraid of cheaters you can create a session only for you and play it alone without some features but enough to finish almost everything by yourself. There is also the multiplayer,which received along the years manny content updates. The strangers and freaks,the side missions and side activities represent a huge chunk of the game ,it's amazing how much details and work they put into these. It keeps updating frequently to engage it’s audience and deliver the working keys for the various games like HellCat, Calibur, Dirty Bomb and many more. FreeSteamKeys is one of the most popular website for offering free Steam Keys. In single player mode you'll find a long and beautiful campaign with over 70 main missions and 3 endings,that alone is going to take over 30 hours if you rush it but i advise to enjoy and explore everything because it's worth. Users can go to that sites to grab one key. Grand Theft Auto V is that sandbox open world experience that keeps you busy for 200+ hours in single player or 500 hours or more in multiplayer.
