Have you used a Competitor Price Tracking? what problems have you had?

I’m aiming to build a Competitor Price Tracking for ecommerce, I’d like to know your experience with these tools. I have some question that I’d like to know from your expertise

  1. What problems have you had with this kind of tools?
  2. What you like the most of these tools? Features and more
  3. What would you like to see in a usable and user friendly Competitor Price Tracking?
  4. How many time are you spending a week monitoring prices? How often do you check this kind of tools

Thank you in advanced if your answer some of my questions!