Which type of reflector should I get?

[SimplyCanon]

I am debating between these two reflectors. Does it make a difference if I purchase a circular reflector instead of a rectangular one? They are very similar in size. I will be shooting senior portraits. Thanks for the info!

Amazon.com: Westcott 301 Photo Basics 40-Inch 5-in-1 Reflector: Camera & Photo

Amazon.com: Westcott 42 inch 4-in-1 Reflector Kit Gold/Silver: Electronics=