actually afaik MS DONT support steamVR.......... SteamVR supports the windows headsets..... this may seem trivial but it honestly is not and if you think about it the reasons should be glaringly obvious
As a rift user, steamVR is a poor relation to native support, and you have the added issue with a lot of titles which are designed to use the vive wands that they map really poorly to oculus touch.
look, if you do not care about any of that then fine, buy one!. as i said MAYBE steamVR integration will be flawless, i hope it is!..... but I have been through the headaches of steamvr crashing or burying me in the floor, as well as having to angle my hands at crazy angles as the touch maps weirdly to the wand controllers, and general poor performance... All i was saying was if it was me I would wait till its out and see as you have nothing to lose.
and as for who cares if they support the vive or rift? well YOU might, if the windows VR HMD goes the way of kinect or zune and then the next time you buy another brand of VR hmd all of a sudden all of your MS store titles are now worthless.
shesh! i didnt think it was such a big deal!.
(that said i didnt know steamVR was in open beta for everyone, so that is a bonus last i saw it was for developers only).
it says it is for developer but if you ask for a key they will give it to you anyway.