How effective is JetPack plugin for WordPress Bloggers?

When you want to take care of your WordPress backend, there are plenty of plugins that can automate some of your operations. And Jetpack plugin from the WordPress creators is one such option. For example it can get analytics for you. Block the spam. And also they are having Image CDN for free. Like this many such small features are available. Though other features such as Video uploads, WordAds are part of premium plan. So I was confused if it is worth upgrading to Jetpack premium. 

If you have used Jetpack plugin in WordPress, how effective do you think it is for bloggers?