Based on the users' reviews of the Spiral Stair 3D app, here are three cons and pros: **Cons:** 1. Some users found the app's graphics "dated" and "not as realistic" as they expected, making it difficult to visualize their stair design. 2. Several reviewers experienced "stuttering" or "lagging" issues while using the app, leading to a poor user experience. 3. A few users were frustrated by the app's limited customization options, which they felt restricted their ability to create unique and personalized stair designs. **Pros:** 1. Many users praised the app's ease of use and intuitive interface, making it simple for anyone to create a stair design with little to no experience. 2. Reviewers appreciated the app's ability to allow them to visualize their stair design from different angles and with varying materials, which helped them make informed decisions. 3. Users were impressed by the app's ability to generate accurate and detailed 3D models of their stair design, which they found helpful for visualizing their project.