I haven't and I guess it is kind of unlikely that any other VC users have. Or if they have they may not see this post so I'll offer my thoughts.
My best guess is that it will either do nothing or make things worse as far as VC recognition accuracy is concerned.
It looks like it is a noise gate, not a noise filter so that probably means that as soon as the volume is high enough, it will pass the entire original audio including all the noise. This could be seen as either bad or good. It will prevent really quiet sounds from triggering commands. If you see this happening a lot then it might help you.
I believe that the SR engine already has a certain amount of noise handling capability built into it and it is possible than any kind of extra noise cancelling is only going to confuse it, unless it is really excellent.
That is not to say that a really well engineered noise cancelling microphone won't work well, because it will, but a software only filter is not likely to help.
Short of a better microphone I think you will have better luck using a better prefix and keeping VC in standby, or modifying your command structure and phrasing.
Of course, this is just my opinion and I encourage you to try it and let us know. It would not be the first time I was surprised (or wrong) ;P
