FarCry4 is good and comes with improvements over FarCry3, but if you haven't tried either get FarCry3. FC3 has several things that make it a better game, the acting, the quality of characters, the twists of the roles of characters and the story. You never feel lost and always feel on mission in FC3.

That said FC4 is also pretty good. It's pretty amazing in many similar ways as FC3, with the wing suit, quad copter and riding elephants, pretty fun. The scenery is also pretty awesome in some of the quests, but it's hard to like any of the main characters you're supposed to be fighting for, which is unlike FC3 where you were fighting to rescue your friends, and for the people of the islands, which helps make a compelling purpose to the game (a unique feature typically not part of gaming and put FC3 in a whole new category of great games imo). In FC4 I think they could totally lose the drug aspect, used legitmately only once to put you in an areana, whereas FC3 'used it' to show you the history with your friends and was thus a different aspect/story to the game.

So, if you haven't had a FC experience, get 3. If you love FC then get 4 too, otherwise wait until the price drops to about $24... it's a great game and a good value at 24, just not a totally awesome game. Hopefully the next FC release will provide character choices that are both good and bad, and a gang of friends to 'make it personal' and a story that is compelling.