As with most games, Far Cry 3 is much better on PC, so I won't give it a 10 here. One of the main reasons is the horrible fps on consoles in general, which really ruins immersion and cuts into the potentially breathtaking atmosphere. Nevertheless, it is the same game on either platform, and once you get into it, the game takes you on a thrill ride through the jungles, rivers, mountains, and oceans of this lush landscape.
Animals are legitimately intimidating, especially if you're afraid of something like sharks. A fear of something can make you take completely different routes to objectives throughout the game. And that's a great thing: There's always a different way, you just need to think of it or find it.
I've jumped multiple times from being surprised by predators, such as tigers and crocodiles. I've swam frantically trying to escape the clutches of a sharks' jaws. I've yelled out loud from the intense feeling of falling you can get from different activities throughout the island. (Good thing my fear of heights isn't too bad.) This game can successfully immerse you into becoming Jason Brody. His character development is wonderful, and allows you to connect with him throughout different situations he gets into.
Like I said earlier though, this great experience is undermined by the shoddy console build, so most of my playing was done on PC. However, I did rent it from Gamefly for PS3 first, played it for a good while, and it was easily good enough to purchase; in general, as well as on a more preferable platform.
Regardless, it's a great game. The only shortcomings I noticed were the ugly and intrusive HUD, and of course the fps problem, which I'm sure you all noticed during the first cut-scene with Vaas. But there is much to enjoy if you give it a try.