I think down the line, say 5 years time, most VR headsets will also be MR and AR devices too. But for now you have to pick one or the other. Actually, MR devices like that Acer one can be good because you can do both. But with an Oculus rift, it’s only VR, not MR. Sounds confusing I know.
At the moment, there’s just not enough content for MR or even AR stuff on headsets, so I’d personally recommend a VR headset.