I have a 7" wrist and have tried both. Here is my experience...I ended up selling the 45mm because on the metal bracelet it kept hitting my wrist bone. Was just very uncomfortable. But on the rubber strap, it felt fine and looked fine too. I have a 42mm on bracelet that I just love! It is the perfect size, but I'm also going to buy another 45mm to put on rubber. I'm thinking to put it on a isoframe rubber strap and waterproof it so I can use it at the beach or for swimming. Just my experience, hope it helps.
T.
T.