Well, here in Mexico there are a lot of stores dedicated to bring japanese toys (in fact in Mexico City, the main city in our country, there's a market in which mostly all stores are dedicated to selling japanese toys, j-music, figures and pretty much everything from Japanese goods -you can even find drinks and candy- though prices are really high.) And you can always find japanese transformers.
Personally, I preffer to buy them online. I think the Takara toys have a greater quality than Hasbro's. So a good number of my Transformers collection is composed of japanese figures, I mostly like to get rare pieces or exclusives, and takara always make the better ones. ^w^ So I have a small collection of booklets and cards. I just love the way japanese artists draw Transformers, it's always refreshing to have a different art style than just the western comic style artworks.
Too bad I had to stop studying japanese, I was going really good at my classes TAT but Primus! Sometimes you can't help it... though I'm planning on studying it again once I'm done with school. ^w^