Figma is like Sketch in the browser with real-time collaboration.
With the limited time I had with it, I can already say with confidence that it’s far more polished and production-ready than in my first experience with Adobe XD. It also has three invaluable features that set it apart: real-time collaboration, vector networks and version history. It can handle dozens of designers working on the same document, at the same time without breaking a sweat. Last but not least, this tool is really fast, easily handling 20+ Artboards in a single document.