In reply to Stephen Cronin.

Check out previous surveys from State of the Word talks -- people's top complaints are around plugins: security problems, compatibility with core updates, compatibility with each other, and not knowing which are good.

Jetpack solves all those, and it's telling that all the folks that run millions of WordPresses (Automattic, all the web hosts) support Jetpack.

And lots of other goodies -- I'm keeping up with comments here because Tavern is a Jetpack-enabled site, so I get a notification in my toolbar and mobile apps when there's a reply to me here.