It doesn't directly have a culture field per product, but it does store strings that needed to be localized separately. So I think I would need to have multiple imports to get each culture in. Once for EN, once for FR, etc, and then all of that again for each product type. It seems easier to take care of all of that repetitiveness with the API.

I have no doubt I can succeed with the import toolkit. But it's a one time deal. I'll never need to import anything else, so any learning gained doing that has no long term benefit. Where as the API examples around importing products don't seem too intimidating, but experience with the API will always be beneficial. I guess I have my answer.

On the downside, I haven't seen any examples yet on creating multilingual documents/products.