It's worth it if you are publishing regularly and have an application or something for which you will publish posts regularly. Also, you should be aware that Musing doesn't allow all content.
Some disturbing content may get censored which you should take into consideration. Medium recently got a lot of criticism for censorship.
You might consider using ghost.org as an alternative to medium. They are a open source publishing platform you can set up yourself in your own server.
Thanks for the input. but Medium Partner program and Medium membership is 2 separate things.
I have the intention of getting into the Medium Partner's program when my writing style and discipline gets more polished.