Please help?! Need your opinion?!

Alright, i have been saving up my money to buy an autographed baseball. I am a huge Phillie's fan, and love the players. At my local memorabilia store, i saw two i liked and they both are 250 dollars. one is a Willie Mays signed ball (really like), and the other is a jimmy rollins All star game signed ball. (also really like) I am torn between which one i should buy, because my feeling is that the Jroll ball might go up in price years to come, because it seems he is just getting better; while the Willie Mays ball may never go up because hes already retired. im not really looking to sell these, but it is just nice to know. Anyway, can i have your opinion on which ball i should buy and why?