It's perfectly legitimate to investigate any theory in the scientific manner of falsifiable experimentation, but I'm not aware that can be said of anyone looking for a quantum explanation of consciousness (which is anyways a rather odd quest given that there doesn't seem to be anything needing explanation).

Roger Penrose certainly appears to be a quack when it comes to quantum consciousness and/or brain operation - it seems that he wants to believe it, so waves his hands vaguely in the direction of microtubules as a place it could be hiding, despite zero experimental evidence, or any falsifiable theory. It's not the fact that this flies in the face of everything we know about quantum effects at classical scale and room temperature that makes this quackery - it's the fact that this is just wishful thinking, not science - not the application of the scientific method of falsifiable theory followed by experimentation.