FCoE is not positioned correctly
In my opinion FCoE was pushed into the marketplace a bit too early, unpolished and positioned very badly.
The early claims were that it simplifies management, will evolve along the Ethernet standards, is very flexible and can be used end to end in a datacenter, it's cheaper than a 10Gig Ethernet + 8Gig FC solution.
It got most of these things wrong:
1. It's does not have simple management, it just puts together storage and ethernet admins. And those guys don't really mix up.
2. Can't be used as an end to end solution without an FCF, and that brings the price up a lot. The FCF is usually contained in a converged switch or separately, but I only know of one such product.
3. It's not really cheaper. You can get Nexus levels of performance with Juniper + Brocade combos at three quarter the price.
4. You can't do proper FC zoning without actually using FC switches connected to the converged ones and this kind of defies the purpose of simplicity and ease of management.
5. Computing power for a two socket server has increased to the point where a two port converged adapter is no longer enough and you need a second one in order to run without bottlenecks. Spread some FlexFabric or VirtualFabric icing and you have a highly complex, dynamic and intensely administered cake. And the SAN is usually a serene place, with blue skies and where change rarely happens.
I believe FCoE still has a place in the enterprise, but strictly as a way to get both FC and Ethernet to ToR or Blade Converged switches where you can split the traffic between FC and Ethernet. It can succeed if the industry comes up with cheap converged switches that do just that, while Ethernet and FC people can handle their networks separately.