Obviously both great speakers and will, as usual especially at this level, be a matter of personal preference, system synergy, and room interaction. I've not heard either but did hear the original 5a well set up at a dealer for an extended demo with my music and they were quite awesome. Assuming you can't hear both and that you likely won't be disappointed with either, I'd go for the Vandys for their powered and adjustable bass, adjustable rear tweeter to fine tune treble, and time/phase alignment. If the Carbons really are meaningfully better than the original 5a I heard it's really hard to see going wrong or being in any way disappointed. FWIW and best of luck.
