>>What is your take on the dual rotor design?

It makes aerodynamic sense - at the expense of mechanical complexity and some other issues I’ll get to.

It's not just a matter of ‘no tail rotor required’. Think about a standard rotorcraft going forwards: the part of the circle where the rotor is the same as the airframe is going faster through the air than the part that’s going the other way. This is somewhat corrected by changing the rotor’s angle of attack as it goes ‘round, but what changing rotor angle of attack can’t fix is when the airspeed of the rotor going ‘away’ from the forward airflow drops to or below stall speed. I would expect a second counter-rotating rotor to mostly cancel this out (although it probably feels weird as hell to have your lift alternating sides). So a higher top speed. A second rotor for lift means a smaller rotor diameter is needed, so a more agile craft, same as a fixed-wing with shorter wingspan.

Besides complexity, another downside I can see is getting into autorotate if there’s an engine or gearbox failure will be more difficult. I’ve met one pilot who got one of the big Sikorskys (fore and aft dual rotors) into autorotate when the gearbox went bang, so it’s… not impossible. Also, like the Bear (the Sov bomber with counter-rotating props) I’d expect it to be stupidly loud.

Fixed wing guy here. Tried my hand at rotorcraft; I was terrible as I couldn’t unlearn some reactions — but I made a point of learning how they work (the TL;DR of which is that they’re all mechanical nightmares). I’m def not a rotorcraft expert, just working out what a second rotor would do ‘out loud’.