I have worked in a few "co-ops", and "collectives", and mostly in a union shops. The difference is all about power. Not pay. Not benefits, nor guaranteed employment.
When a "collective" works well, it is very flexible to the needs of the workers. It operates on a human scale. Decisions happen from the bottom up, rather than the top down.
You might be surprised how productive, and how efficient a "collective" can be. Just by removing the managerial level.
I once worked in a printing co-op.
About ten members, all sharing equally.
This plant had a big beautiful kitchen, where we all cooked and ate lunch.
Most if not all decisions were made around that kitchen table.
As you walked into the kitchen you’d see this big sign:
“This is Co-Op, we practiced the art of printing.
If here together, we can solve,
Money,
Sex,
And The Dishes,
Everything else will work out just fine.”