I don't use Docker much now, but in my experience the reliance on Virtualbox (on Mac) was a little clunky and annoying, and I really wished for native support without Virtualbox. I'm super happy to see that's here!
We have been using Vagrant and VirtualBox heavily and the new Docker for Windows/Mac is making us reconsider that since you can't easily use more than one hypervisor on the same dev machine without some hassle. We might be building our Vagrant boxes for these other hypervisors soon. VirtualBox still seems easier to work with but there isn't anything much exciting happening with it lately.
Let's see...