You can still use breadcrumbs on the page, either way. Duplicate content and crawlability are the questions here. Could a product appear in multiple categories or just multiple subcategories. If just subcategories, maybe try removing subcategory from the url structure. If it could duplicate across categories use the canonical tags to point to a single version. I think it's better to use the longer structure either way. Look at the best in the business (amazon, etc) and they all use /category/subcategory/product not just /product.
