My opinion...
CRM is a great concept and tool, but it is useless without detailed, explicit SOPs. We follow the SOPs....one guy keeps tabs on the other. Both, then, stay out of trouble. On many occasions, good CRM has kept me out of trouble (and the Chief Pilot's Office).
A good F/O is worth his weight in gold.
The problems with CRM that I've experienced is the F/O 'correcting me' when I am, in fact, following the SOP, but he has no idea what he's talking about. I remember one time, the F/O (who demonstrated an attitude on several previous occasions) consistently failed to make required callouts. When I brought this to his attention, he argued with me. So, I asked him to get out his book, so that I could show him....he refused.
Things worked out well for me, however, because the next stop was at a hub/crew base. He suddenly became ill and got off the trip. While he is still a problem child, he's no longer my problem.
CRM, too often, is thought of as making the cockpit a 'happy/clappy' work environment. In fact, it is a management concept that promotes the use of all available resources to achieve a safe and compliant operation.
Complete and correct information and situational awareness are vital to proper decisions. This is where a good F/O comes in handy. On the other hand, however, bad information given to me by the F/O is much worse than no information. That is, if you don't know something, please say so. Don't feed me XXXXXXXX (nonsense), because I listen to my F/Os, and I make decisions based on the information I have.
Just my two cents.....
Fly safe,
PantLoad