it's love it or hate it kind of game. i enjoyed what i played and wish i had picked it up when i had money, but it's really up to you. i'd say rent it if you can. fc3 looks promising but there's too little information to form a standing opinion on it.
I played through most of FC2, but my save became corrupted and I couldn't finish. Classes kept me from playing through again and I never finished the game. I liked the open world exploration, hated the 30sec re-spawn of enemies at checkpoints, and loved
the stealth aspect of the missions. Overall, I thought it was a good game, but horrible at hiding the fact that it's just a game.