Don't get me wrong, when Craft Sync all goes smoothly syncing a large complex proto with many screens is a time saver..........But it all falls apart when you pick up a file you didn't create. Syncing can't move between Sketch and PS. :-(
Lets say UX-er 'A' creates a full working Sketch Ruby demo and it is approved, all ok so far... Then say Designer 'B' picks up that sketch ruby wireframe demo to style the elements and then is unable to open the file because we are not allowed to run sketch in-house instead the designer has to resort to trying to manage and update hotspots in that template via differing software, say PS CC17 with craft sync. Do not try this. This can be a nightmare. I am finding the old flow of exporting screens as PNGs and dragging em in is way more robust to share wireframes and that I would recommend to the community to never jump out of one software to the other with craft sync.
Also it is such a shame that the constant craft plugin updates often break the complex syncing too. I hope Invision team understand firewalls inside companies are only going to increase security and the limitations on syncing via craft smoothly even if ports are unblocked by your IT dept.