Should there be different login pages in terms of look and feel of a single company which has multiple products?

I'm evaluating one large application which has different products and each product has unique visual design for its login page. Now though products falls under same company their customers may purchase individual product and not complete suit.

So I think there should be uniformity in terms of design across all the products, though they will be sold individually. Now I still need some opinions on this for better UX. Any valuable insights are welcome.