This answer will refer mostly to the United States...
5 years ago when this question was asked, I knew less than I do now about contemporary cooperatives, worker-ownership (employee stock ownership plans), and the like. I still don't know as much as I'd like to for a thorough answer, but I think I know enough now to point some things out:
*There is a sizable cooperative and worker-owner movement in the United States. It has been quasi-political for a while, but it is now becoming much more politicized ...especially with the help of the DSA, Bernie Sanders' presidential campaign, and various legislation that himself and others are trying to push through at the national level. For instance, H.R.2357 ( https://www.congress.gov/bill/115th-congress/house-bill/2357/text?format=txt
) is a bill to establish a national bank, funded by taxes, that would invest in new co-ops, ESOPs, etc. and fund the movement of existing non-coop businesses towards worker-owned models. AFAIK, most anarchists have taken very little interest in any of this ...but that's just AFAIK.
*The above is definitely NOT anarchist. It is just as statist as the State's investment in capitalist firms. However, it is a departure from capitalism and it is far more democratic than Marxist-Leninist dictatorships. Some of what I want to look into more is the extent to which coops would be regulated by something like the above investment bank, but at least at the outset the dictatorship of coops/collectives/communes by the Party doesn't seem to be a goal.
*That said, there are anarchist (or, anarchist-friendly) ways to think about this all without throwing it entirely onto the dung heap. The DSA now has an official Libertarian Socialist caucus ...which is one approach. A push to detach coops from the State could be another. A push to confederate coops and prioritize distribution of surplus to commons (or, communes) could be a very anarchist-communist approach. There's a lot of potential thinking and experimenting which this all offers anarchists.
*There's a lot more to be said about these things in relation to the Service Sector, the so-called "sharing economy", to the increase of automation...
*As far as the power dynamics of coops themselves go, it varies ...widely, with a lot of factors involved. Obviously not all coops share the same anti-authoritarian goals as anarchists. There can be a lot of workerist and/or producerist ideology tied into it ...neither of which are in my interest as someone that wants to work LESS.
IMO - I think that pushing on these contradictions could be highly beneficial for anarchists. And as an anarchist, I think that cooperative work is much more beneficial to me than waged labor and hierarchical management.