The plugin works, hence the one star. WordPress is open source, so improvements have to be shared, and however reluctantly, WordPress.com decided to eventually share. One shiny star for you!
However the connections to WordPress.com for modules that don't need WordPress.com are unacceptable -- requiring all your non-Wordpress.com multisite users to register first at WordPress.com.
See what I did there? I'm copying their WordPress.com writing style at WordPress.com from WordPress.com sponsored by WordPress.com which appears in headers, overlays, plugin descriptions, and elsewhere, bragging about WordPress.com on your non-Wordpress.com site while saying you are getting WordPress.com functionality without using WordPress.com.
WordPress.com! Wee. Fun.
It's even called "Jetpack by WordPress.com." Thanks, guys, I nearly missed that connection.
So, if you have your own multisite, in many situations, you are going to be offering your time/services which may be in competition with -- you guessed it -- WordPress.com.
Typically, they wouldn't be in direct competition, and your multisite is a niche thing with specific benefits that ugh WordPress.com cannot, will not, and does not offer. However, do you think your less-web-savvy users will understand that? Maybe not.
And, yet, your users have to go sign up on... that other site... in order to use your multisite.
This is all so completely, totally, and utterly obvious that clearly someone in the WordPress corporate offices decided, "Screw 'em. Because money." So: One star! Enjoy it!
And shame on the dot org folks for letting this slide. No stars for you.