I've found that many "prompted" reviews are generally of low quality and lack detail, and essentially flood the listing with useless information. (Who cares if there are 500 reviews each saying "Good app!", that tells you basically nothing.)

In 7 years I've never prompted for a review in any of my apps. Users that write reviews do so genuinely, and if they are happy, they often leave extremely detailed feedback explaining why, and that is much more valuable to me.