Sketch

😐 Mac only
❌ File based, no version history
❌ File based, one user per open file
❌ No dev inspect tools, requires external app like Invision
❌ No prototyping, requires external app or plugin
❌ No commenting/feedback, requires external app like Invision
✅ Responsive constraints to adapt components
✅ Symbol libraries can be linked to multiple files, pushing change updates
✅ You can work on a file without and internet connection
✅ Relies on plugins to extend functionality, like sketch runner, sketchmate, which increase sketch's power and abilities

Figma

✅ Web, Mac, PC, Linux
✅ Version history
✅ Real-time multi-user collaboration
✅ Dev inspect tools
✅ Simple prototyping
✅ Simple commenting/feedback
✅ UI of features and shortcuts based on Sketch
✅ Responsive constraints to adapt components
✅ Components can be used for individual files, or team libraries manage them across multiple files and users, you can attach notes to each component
✅ You can save a figma file, and work on it without a connection, and re-sync it with the system when you have a connection again
❌ No plugins, so the community's main feature requests are being added as core features