For developers looking to build canvas apps or product teams needing real-time collaboration, choose tldraw. Its polished interface and unique features, like the ability to turn sketches into working UI, make it a strong fit for situations that require a more refined output. However, be mindful that commercial use requires a paid license, so if you're working on a budget or need full open-source capabilities, tldraw may not be the best option.
On the other hand, if you're in need of a simple, charming tool for quick sketches or brainstorming sessions, Excalidraw is your best bet. Its open-source nature allows for self-hosting and offline use, making it great for those who value local data storage and the ability to customize. However, if you're aiming for high-fidelity visuals or a comprehensive design tool, Excalidraw will likely fall short.