Get Serious

I was joking about using ViVi magazine as my learning source for my trip to Japan (it was just a good excuse to pay $20 for a magazine). Instead Matt is trying to teach me a little Japanese so I can get by...I'm a little skeptical about my learning abilities but I'll give it a try. To facilitate my learning, we are looking into two learning sources:

Genki Japanese

Or

Rosetta Stone Japanese

I almost feel like I won't have enough time to use Rosetta Stone. But I hear it is pretty effective. Am I really going to learn Japanese or should I just stick by Matt's side the entire time and be in my own world when anyone talks to us? I think it's worth a try, but is it worth a $500 try or $40 try?