If you're a developer looking to build custom canvas applications or need real-time collaboration with a polished interface, choose tldraw. Its "make real" feature is excellent for product teams aiming to transform sketches into functional UI elements. However, be aware that commercial use requires a paid license.
Conversely, if you prioritize an open-source solution and need a quick, charming sketching tool for brainstorming, Excalidraw is your best bet. Its hand-drawn aesthetic makes it perfect for rough designs and quick architectural sketches while keeping your data local. It's not ideal for highly polished visuals, but if you value simplicity and flexibility, it's the way to go.