I had a briefing this month with a vendor whose product currently supports VMware ESX and that the company says will soon support Hyper-V. I've heard the same thing from vendors for a long time.
I hear pretty much the same story from many IT pros in the trenches. They like Hyper-V, especially its price, but its other features too. They're actively testing Hyper-V in their environments, and technologically, it's competitive with the alternatives. But they're not using Hyper-V in live environments.
The specific vendor I mentioned above was Embotics. A new version of their V-Commander software was released on Jan. 12. V-Commander is a virtualization management suite that helps to automate a virtualized environment and provide functions like performance management, VM usage reporting, and automation. This version adds several new features, including improved reporting the ability to enforce your management choices--you can prevent a VM that's not supposed to run from ever starting.
During our conversation, Jason Cowie, VP of product management at Embotics, said V-Commander currently only supports VMware, but full Hyper-V support is planned to happen within about six months. Cowie said he's heard that System Center Virtual Machine Manager (VMM) 2012, likely to be released this year, is supposed to add a lot to Hyper-V's capabilities and could spurr increased Hyper-V adoption.
Information on VMM 2012 is pretty sparse right now, but check out this blog entry to see if it'll be enough to move your production environment to Hyper-V.