Atlas documentation falls short...
Way back when Atlas was first annouced and Microsoft was just starting to get into the game I posted a HUGE request to the forums (which has been since deleted) that the single, most important piece of documenation that is a MUST have is a detailed summary of what OS's and Browsers/Versions on each OS is actually support on a feature by feature basis. `
It is not in the current documentation online as of this morning.
To me, it would seem that Microsoft would have to have this peice of information already at their fingertips but hesitate in making it public. They do have a complete feature list which is slated for this release. And it is also obvious that they do have all the different environments available and have tested Atlas on every single environment; which means they know what is and what is not supported on each and simply do not want to share it.
My last two remarks on that original post to my blog still stand true:
"I think if MSFT really wants the industry to adopt this technology they will need to prove that it has a wide support base in the industry. Given this matrix it would allow us to really narrow down our browser/OS targets and enable us to make a more educated decision."