What game is better battlefield bad company or bad company 2

It really depends on what you like, I personally prefer the 2nd installment (mainly due to the graphical improvement and the great destruction engine. But really, you need to test them out, because the weapons and gameplay changes, truth be told, they are pretty typical fps games, with both games being very comparable to the Call of Duty series and quite a significant amount of other titles. So really, try them out.