Any big difference from going 15 inch to 17?

I am looking to get new tires for my car and it currently runs 15 inch tires and wheels but can accommodate 16s and 17s. The ones i am looking at only start in 16 and go up to 17 but they are quite a bit more expensive than all 15 inch options. So are there drastic pros/cons going up to 17? I have seen people saying 15 are better than 17 and vice versa.