I’d encourage Daring Fireball readers, whenever they encounter these “Please rate this app” prompts, to go ahead and take the time to do it — but to rate the app with just one star and to leave a review along the lines of, “One star for annoying me with a prompt to review the app.”
That has been my mobile app review policy when it comes to apps that stop you in the middle of doing something to ask to go review the app. I suggest that mobile apps have buttons for ‘leave a review’ in the settings section of their app instead of hijacking the work flow of their users.