Have you heard of/tried Marvel App? (marvelapp.com) I tried InVision but the syncing between sketch and Invision was so laggy I couldn't deal with it. I found Marvel and have been happily giving them my money ever since. Granted I am not really a "designer" so I'm not in it every day but I really like how easy it is to sync and it's pretty well integrated into Sketch:
http://cloud.cityzen.com/2281d62e5564
You can see there that the Sync buttons for Marvel sit right on top of the list of artboards. Pricing is on point as well.
You can see there that the Sync buttons for Marvel sit right on top of the list of artboards. Pricing is on point as well.