I go to reasonable lengths to keep my site fast but I also love some of the features. I am careful to only have the modules that I want to use enabled.
Stats of one of the modules I like to keep an eye on. I also have Google Analytics but Jetpack Stats are easier to access along with other site checks.
However, https://stats.wordpress.com/e-201341.js has the longest load time of any other aspect of my homepage. Longer than photos, longer than much much longer html, js, jquery, css etc.
My homepage on this pingdom check (http://tools.pingdom.com/fpt/#!/d985YP/https://woodworkingmasterclasses.com) took 890ms to load the stats query to wordpress.com took 752ms.
Why does it take so long?
One simple reason is that this particular subdomain of wordpress.com is secured with a godaddy ssl certificate. The ssl 'handshake' alone takes 213ms.
Simply upgrading the ssl certificate of the stats.wordpress.com to something quicker like GlobalSign would probably bring down this load time by a third.
I love Jetpack.
Please make it faster.
Start with a faster ssl provider.