When it came to vintage binoculars which was better? Bausch & Lomb 9x35 Zephyrs or Bushnell Broadfields? And how do Leupold's stand up next to these two binoculars?
That is a bit of a head scratcher. I have a collection of older vintage porros, and in my searches I have never seen a Bushnell Broadfield.
However there are a couple of Japanese vintage porros that are the physical and optical equal of the B&L Zephyr. Zephyr Eremicus, Zephyr, not Zephur. I think the parts even will interchange and if I switched the prism plates I seriously doubt anyone could tell them apart. Bak-4 prisms on all of them, which was a step above most of the vintage porros. The Bushnell variant is the Bushnell Featherweight. Cannon's standard porro (no model name I've ever seen) is the other. Note also that in the last days of the Zephyr, the production switched to Japan. These are often referred to as "standard field" and all magnifications were in the 7*+/- range, say from 370-390' at 1,000 yds, depending on magnification.
There are a couple of other vintage Bushnell models that are optically right up to modern standards too. One is the Bushnell Custom and the other is the Bushnell Rangemaster. They are however quite physically different from the Zephyr, and the Custom can easily bee seen as the precursor to the Rangemaster. The Rangemaster is often held as an example of the best widefield binocular ever made, it is 11* or 578' at 1,000 yards. Kind of sci-fi looking and brings the thought that these look like something George Jetson would have.
I also had a Leupold Gold Ring 9x35 for a number of years and the design looks like another dead ringer for the B&L, Bushnell, and Canon. ETA, I bet the parts on the leupold would also interchange with the others too.
Any of these will do to hunt with today if they are clean and collimated.