If you're a developer keen on building custom canvas applications or working collaboratively with your product team, choose tldraw. Its polished infinite canvas and real-time collaboration features make it perfect for brainstorming and design processes. However, be aware that if you plan to use it commercially, you'll need to upgrade to a paid license to remove the watermark.
On the other hand, if you're a frontend developer or indie hacker looking to quickly generate functional UI from prompts, opt for v0. It delivers real React/Tailwind code, allowing for fast iterations, especially if you leverage Vercel and Next.js. Just be mindful that its output is tailored for the React ecosystem, and credit-based limitations may apply if you use it extensively. Avoid this if you're not working within its specific tech stack or need a broader site-building solution.