The adidas Superstars typically have a shell toe, and have a little bit more arch support than the adidas Originals version shoes. Also, the two will have different styles and colorways that are offered.
The adidas Originals Superstar 2 - Men's (size 7.5), will be the equivalent to a "Women's - size 8.5". The "Men's" version will be slightly wider (D - Medium), than the "Women's" version (B - Medium). The shoe itself as far as materials and feel will be the same for both.