Accurate but infuriating to save
Measurements are fairly easy and seem to be quite accurate on my iPhone 13 pro, but the paid feature allowing saving of measurements is not intuitive. The process once finished is to press the photo button, which is worthless if you don’t scoot back to see the entire thing, and then you have to hit share and save to file before it actually saves the measurement. Any divination from this step removes all progress. Once you hit finish it should just save the measurements. Picture can come later.