I've been using it for a year for my open source projects before I had a Figma license for contract work. I'd say it's VERY capable, performance can be iffy with enormously big files, but generally on-par with Figma. Their workflow is closer to webdev, so handover to devs is easier, but they lack some of the neat component magic of Figma (last time I've seen they don't have component changes for hover/click states for example).

That being said, it's FOSS, anyone can help, they will never have a rugpull like almost getting bought by Adobe.