Our small design firm has used Figma a few times on large apps with hundreds of screens, and we prefer it to Sketch.
It's smooth in the browser, although we use the desktop version which runs remarkably well on Electron. Files auto-save instantly and you can do all of the fancy animations and effects that Sketch offers.
The killer feature for us is inviting clients or other designers into the document whilst editing it in real-time like Google Docs. Clients can lock themselves to your viewport so you can talk them through the design (huge win for me, the clients love it), or they can browse around freely and edit the document if you allow them.
It's smooth in the browser, although we use the desktop version which runs remarkably well on Electron. Files auto-save instantly and you can do all of the fancy animations and effects that Sketch offers.
The killer feature for us is inviting clients or other designers into the document whilst editing it in real-time like Google Docs. Clients can lock themselves to your viewport so you can talk them through the design (huge win for me, the clients love it), or they can browse around freely and edit the document if you allow them.
Figma should have more market share IMO.