I have used VPX5 with DualEyes (since PluralEyes was not then released for Windows OS.)  My project included two camera input (with audio on each) and two separate stereo audio recordings.  Putting the four files into DE and having it synchronise the audio was quite straightforward - one set of files for the project ran for 1 hour 5 minutes continuous but DE "adjusted" the audio files so that they matched perfectly with the camera audio for the entire 1 hour and 5 minutes.  Multicam editing in VPX and synchronising with the two independent audio files was thus VERY straighforward.

I now have PluralEyes but have not yet tested it fully with VPX.  However, I did put into it the two camera files mentioned above, together with the audio file which was a "mix" of the previously-two separate audio recordings, and PE successfully aligned all the files on its timeline.  What is not entirely clear is exactly how this would be transferred to VPX but I did not try to "Export" the file(s) from PE.

To jeffjn I would say the biggest "problem" with  synchronisation of "longer-length" multicam audio (perhaps with separate additional audio files, as in my case) is that the audio can "drift out of (lip-)sync".  DE and PE can automatically correct for this.

HTH

Jeff