Hi Jahel,
You should check out
Litmus. It's very possible using their tracking codes to determine noy only mobile/desktop, but what kind of desktop/OS used, what kind of mobile platform, as well as duration of email views, forwards-to-friends, and who printed the email.
Litmus plays very nicely with Marketo, morevoer, and doesn't need much configuration to get tracking. There are really good discussion threads on the community to steer you in the right direction,
like this one.
Hope this helps, and good luck with your analytics!