its a good game, very good graphics and awesome free roam.
good missions, and loads of stuff to do, a completely dynamic and changing world, where you can do pretty much anything, like get a job, buy stuff from shops, have a house. It is the best RPG i have played.
But after a while, living in a whole new world loses it's novelty because you already have a life, so why buy another?
A very good game, 15 pounds is a good price, but beware, very addictive.