Firstly if you haven't ever played a Just Cause game, why not?
personally I think that JC 1&2 are some of the finest open world 3rd person action games out. Game worlds on both games are huge and expansive and the amount of side missions and collectibles throughout both titles will keep you entertained for a long while. That said the main draw to these games for me is the amazing visuals, vehicle combat, gun play and insane stunts that can be pulled off when ever you want. JC 1 is brilliant but the side missions can become a little repetitive after completing a few. JC2 is as good as the first game and better, with a better engine, better game mechanics (Such as grappling and hang glider combining to create some really fun and hilarious outcomes, has to be seen to be believed what you can do in this game, it is quite crazy).
Overall both games are immensely fun with JC2 being my favourite of the bunch due to the plethora of improvements and the fact that you get both in one pack makes this an absolute bargain!