I would say that the $25/month plan is a bit pricey for what you can gain from MS - I have found an uptick in Medium views (and in views on other stories) when I share at MS (I don't pay for the distribution plan). I would note there is a ton of content shared there, and being featured helps (You can't really pay for that) - MS emails you every time your story is shared with 10, 20, 50 viewers and so on - so, it's a lot of emails to let you know "something" is happening.