Sidenote for anyone who doesn't have an international data plan normally, most plans have a temporary one you can add. I have AT&T and I think it was just $10 a day for each day you used it internationally, short trip so it was worth it for me. The GPS can be a little finicky with it though, spent a lot of time walking in circles the wrong way trying to get google maps to work in Tokyo. But you see cool crap along the way.
I have a "Bad Elf" that I pair to my iphone and it's amazing. A sick level of accuracy, but it still can get a little wonky when you're doing the airline pilot "crap, which way is west?"