I will hold out on offering a comment on that until I’ve done a proper side by side taste comparison.
But it’s a great question and it’s a real opinion divider. I recently had a chat with Douglas Weber of EG1/HG2/Key fame about it. I met him at MICE which is a coffee exhibition held in Melbourne.
My opinion is that the hybrid combination of conical then flat makes a difference in that it yields the best of both body and clarity.
Doug is convinced that if a burr set has the right height and geometry, the top part of the burr acts as a pre breaker like the top burr in a hybrid set. He pointed to (literally) the Mazzer Robur 83mm conical burr set in the Weber Key as an example. And what he was saying in respect to the Robur is 100% correct. I agreed but suggested that while the idea of the Robur burrs being tall enough to act like a pre breaker and finishing burr set all in one, that it was still a conical burr from top to bottom, unlike the DRM hybrid.
Interestingly, Kafatek’s MC series, with the latest being the MC5, has dual conical burrs in the one grinder. In that case Doug’s theory might hold up.
My conclusion is always based on what I can taste but that aside, I am convinced that any change in input (burr geometry / hybrid / dual) is going to result in a change in output (flavor / viscosity). It’s just a question of whether that change is significant enough to be detectable.
As a side note, I personally think that Doug is chock full of integrity in that he won’t create a hybrid simply to generate more sales. He said words to the effect that he has to be confident that it would be a genuinely different in-cup experience. Whilst our opinions differ, I certainly have respect for his and for his philosophy of creating machines that make a difference.