I played the crap out of it and enjoyed it quite a bit when it first came out. I got to right near the end with only the main forts and a few other random missions to do. ( I don't collect all the hands and necklaces and junk. Only pick them up when I find them natch.)
But the mistake I always make with Far Cry games is to manically craft the best stuff possible and a soon as I have it and all the talent points I want I get a bit bored. I will say though that Sabertooth and rare Sabretooth are best pet. Dat speed. Bonus points to the cave bear as well just for being so huge and intimidating. Oh and once you get insane bombs the Owl can pretty much wipe out any camp while you chill and laugh in cave man which I imagine sounds something like "Wenjaahaha we brah no ibly!"