What are the concrete benefits?

Do they tend to make greater revenue or profits? Pay higher wages and offer greater benefits to employees?

Coops tend to have better aligned incentives for employees on every step of the ladder. They'll tend to be more conservative about R&D but ensure that money that's being spent is being productive for the continuing health of the company since instead of that budget being "corporate's money pile" it's your potential profit share.

I think there's also a tendency towards longer tenure and higher value employees due to the investment in the company's future being a sort of central tenant of their attractiveness.