Wellcome to VOX support forum!
VOX Collections are unique because You can add to them music from many different sources. Local tracks, SoundCloud, Spotify, LOOP cloud, Radio... And all this together in one collection. It extends the idea of a regular playlist, and it's the main reason, why there is no ability to sync these collections between devices or platforms, yet....
It's difficult to implement because there are tons of different scenarios and we have to consider them all. We can't release the raw solution. Users spend a lot of time collecting all together. When we'll release such solution - it has to be thought out and complete!
We are looking forward to it, not less than You! Let's hope it will be available soon. Stay tuned!