My only rangefinder is a cheap Bushnell. But, I own two identical spotting scopes, one Zeiss and one Leica. Both are 20-60 zoom; Leica is 77mm objective; Zeiss is 80mm objective. Both scopes are around 8 years old and sell in the same price range. So they are nearly identical in all respects.
I recently set both of them up on my front porch and at 60x, spotted on neighbor's garage door knob about 700 yards away. It is almost impossible to detect a difference in those brands. Both show the knob clearly. But I do believe the Leica image is just a tad more crisp.
This may or may not apply to a rangefinder. Point is, both manufacturers produce very good glass.