Key Biscayne or Miami for Sony Ericsson?

Hi, I'm thinking of going to the SE tennis tournament in 2012. I’m thinking of staying for 5 nights though I’ll only be going to tennis for 2-3 days. I'm not sure if I should stay in Key Biscayne or Miami (and drive over to the matches). My guess is that parking in Miami is difficult and expensive (and I don’t enjoy driving). But, I’ve stayed in Miami Beach a couple times and like the area. Is there transportation from Miami to Key Biscayne? Or is it a hassle getting to Key Biscayne from Miami (no matter what the mode of transportation)? Your thoughts would be appreciated.