We installed the plugin and we got our web site down for 3 hours because of high CPU ussage. We usually consume about 3% of CPU during high traffic times of the day. With the Jetpack installed, we reached 20%, so our hosting shutted down our server. We quickly uninstalled Jetpack and everything was back to normal again.
I'm so upset that you force me to change WordPress.com Stats which functions perfectly, with that anoying blue message... to this piece of crap that has so many functions I don't really need. They should be different plugins not an All-in-one installation.