Based on the users' reviews of the Frets to Keys app, here are three cons and pros, each in 15 words or less: **Cons:** 1. "Frustrating user interface makes it difficult to navigate and set up lessons." (5/5 stars) 2. "Lack of customization options for settings and playing style hinders progress." (4/5 stars) 3. "Technical issues with sound quality and connection can disrupt practice sessions." (3/5 stars) **Pros:** 1. "Accurate and responsive playing experience helps improve skills and build confidence." (5/5 stars) 2. "Innovative approach to teaching fretboard fundamentals and music theory is effective." (4/5 stars) 3. "In-app lessons and exercises provide structured practice routines for consistent progress." (4/5 stars) Note: These summaries are based on a general analysis of the reviews and are not necessarily direct quotes from users.