Choose Excalidraw if you need a simple, charming, and quick way to brainstorm ideas or sketch out concepts. Its hand-drawn aesthetic is perfect for low-fidelity presentations and quick architecture sketches, making it ideal for solo developers or small teams wanting a straightforward, local solution without the clutter of high-end features.
Opt for Figma if you're part of a design team and need a robust tool for creating polished interfaces and collaborating in real time. It excels in managing design systems and offers extensive community resources, which can significantly speed up your workflow. However, be prepared for potential costs with larger teams and ensure your devices can handle the heavier files. Avoid Figma if open-source flexibility is crucial or if you require complete offline functionality.