I didn't enjoy GTA: IV much at all and decided against getting GTA: V. But given the incredibly hype built up around it as well as the "OMG IT CHANGE GAMING FOREVAR" comments I kept seeing from these forums as well as everywhere else, I decided to give it a try.
I haven't been this disappointed by a game since Brink. A disjointed single player campaign combined with generic, unlikable characters made for a tremendously unpleasant experience. Bland, unimaginative, and it might as well have been called GTA 4.5. The map is vast but lifeless with little to do in the countryside.
The GTA Online portion was repetitive and tolerable, but overall I don't see why so many players are hailing this as something that will change the future of video games. Felt like a shallow experience to me.
Maybe I missed something that you guys didn't.