I think it'll be much better than DX11, but reliable sources say that MS & NVIDIA are colluding to make various features exclusive (to punish AMD / Khronos), and generally gimp it. Plus it's Microsoft.
Vulkan looks genuinely exciting, and doesn't come with any attendant walled garden. I really hope it becomes the target API for all devs beyond the influence of MS/NVIDIA tendrils.
What sources?