I used Bronica GS1 gear to shoot bicycle racing and triathlon for a couple of different magazines... Not that i consider myself well regarded, except for by my mom.

Legendary cycling photographer Graham Watson used to use Bronica 645 when shooting events.

I chose the gs1 system because of leaf shutter lenses throughout the system. They weren't the toughest cameras ever built, but were great for shooting flash fill from the back of a motorcycle.