If you're an open-source advocate or part of a privacy-conscious team, choose Penpot. Its genuinely open-source nature and self-hosting capabilities give you control over your design assets. It's particularly suited for those who prioritize standards like SVG and value real-time collaboration. However, be prepared for a smaller ecosystem and slightly less polished experience compared to more mainstream tools.
On the other hand, if you're a product designer or part of a design team, Figma is the better option for you. Its robust real-time collaboration features, extensive component and design system support, and a vast ecosystem of plugins and community templates make it an industry standard. Just be mindful of the costs for larger teams and potential performance issues on less powerful machines. Avoid this if an open-source solution is imperative or if you require full offline functionality.