figma is pretty freaken amazing, and it works outside of macs. So overall there is nothing but upsides to it. Collaboration is amazing too. Just... No down sides.
Once you are in Figma, you are trapped forever. No way to get out your original editable artwork files.
Buyer beware!
I could switch to Figma from Sketch very easily because I could upload my Sketch files in Figma and Figma could deconstruct them into layers and elements with even layer names intact!
Vice versa? No.
Even Photoshop files .PSD are readable in many other photo editing apps.
Figma.. no never.
However, the only page I found is https://help.figma.com/hc/en-us/articles/360041060434-Genera..., which says they’re committed to your privacy, but doesn’t mention data portability.
Figma is significantly more expensive than Sketch, e.g. for individuals: $144/year vs ($99 for first year + $79 for next years), and that's if you choose to upgrade Sketch every year, which you don't need to.
Figma also doesn't really work offline.