Olympus EM1 Underwater - in a nine year old underwater rig still an upgrade?

In this video I talk about switching to a nine year old second hand Olympus EM1 Mk1 for underwater photography. I talk about lens and port selection, and the pros and cons of moving from my beloved Olympus TG series setup. I hope it's useful for seasoned underwater photographers and other amateurs, or divers considering getting in to the hobby of underwater photography.