I'll be interested in hearing from anyone who uses this and finds it offers them more than they are currently getting from cygwin or VMware+Linux VM. I realize it's a very different beast from cygwin - an entire User Mode Linux environment, as opposed to being able to download windows versions of the Linux Environment, but, on a day to day basis, It will be interesting to see what people do differently, and why they…
The main advantage over a VM is no resource partitioning: on a 4GB RAM tablet with 64GB eMMC, you can't allocate more than 2GB RAM to a VM without trouble, and putting 20GB of disk aside for it is also a pain., and much improved power efficiency (even an idle VM drastically reduces battery life, while Ubuntu for Windows doesn't).
Compared to Cygwin: a lot more packages are available, a lot more just works out of the box, and you can painlessly use online tutorials for Linux, which often assume Ubuntu and don't consider Cygwin a target platform.