I guess my question is "effective for what": Chest or tricep development?
I have shoulder problems so I don't go extremely low and I also can't lean far forward as you might see some people dipping. the lower you go and the more you lean forward, the more stress you place on the shoulders.
So: slightly leaning forward, down to about 90 degrees. This has helped my triceps and chest.
Complication makes it easy to explain failure.