I'm sorry, I like the idea of JetPack, but it's really just too much weight on the site speeds. It uses about 50% of site resources for most sites I run, which use a lot of plugins. Truthfully, the only tools i use are the Site Tracking provided by WordPress.com. Which isn't really even needed. I actually use Google Dashboard for the analytics information and tracking they provide. I also use google's api for link shorteners, as well as looping through all the social accounts tied to the site. The email subscriptions is ok, but most clients will use MailChimp or another email blast provider that does the job nicely.
As far as the other plugins, the Carousel and Gallery don't work too well, and have bugs. Very slow loading.
Same with the Mobile plugin, I've found it to be a problem with every site. I've found that clean responsive design is far superior than using a User Agent detector, simply because, there are a lot of mobile and tablet devices that don't have the correct User Agents set, especially Android Mini PC's which are becoming the top seller for home computers, and they are running on HD1080p TV's. (so much for user agent switchers). I've found that using a server ready script such as Adaptive Images actually performs a lot better than a user agent switcher. Why deliver 1900px wide images when the device is only 320px or 450px wide? I've got page speed load times low enough for fast delivery on 3G devices.
There are several other plugins by JetPack that aren't bad, but they don't compare to the ones I already use.
I think JetPack needs to be broken up into smaller sections. For now, all I use is a Fork called JetPack lite. Does the job for tracking, and thats about it for my needs.