William S. answered 05/08/20
Live and Studio Audio Engineer with 15 years experience
Thus far, it's a tie between the DiGiCo SD12 and the Avid S6L. They both sound amazing and have massive expandability, they're just slightly different in their workflows. I haven't tried the new DiGiCo SD7 Quantum but I would expect that to be a cut above.
That being said, both of those desks are high end professional consoles, not the type of desks small owner/operators would generally buy. The industry standard for smaller format these days has become the Midas M32 or Behringer X32. They're essentially the same desk, running the same software, they just have different mic preamps, analog circuitry, and physical body parts. My favorite competitor to this, and my preference in this range, is the Digico S21. It's under $10k, sounds a mile ahead of the M32/X32, and it's pretty ergonomic to use.
Those are just my thoughts, your mileage may vary!