I'd go to Japan. I find it's rich history and such to be very interesting. I don't see what fascinates people about Cuba, I think that a lot of the excitement over it is that we aren't allowed to go. Going to Cuba seems almost exploitive to me. I do appreciate it's historical significance but it's kinda of like "hey! there's a place where everyone is poor and it's like it's 1952 because of an oppressive quasi-monarchal government is in place. Let's go take pictures of them." Buy Steve McCurry's excellent book on the subject and read it on your flight to Japan.