I have both and also run Parallels.

The biggest advantage of having the PC version is that it gives better ability to work with the Stylemaker, especially if you use external MIDI files when making your own styles.

Other than this, the development team has done an excellent job of closing the “gaps” between the Mac and PC version over the last few years.

On a side note, I was impressed with how fast the PC version ran on Parallels.