Good PIM But Missing Mobile Equivalent Rated 5 out of 5 stars
It's the best PIM out there. For me Thunderbird IS Lightning.. don't care for the mail client as much. Please make a proper mobile equivalent to sync properly with the desktop version (calendar, tasks, contacts etc.), prefferably not through Google or even offline. Thank you & Congratz for such a good job!
Edit: 2016 and still missing the mobile sync-able equivalent :(
As long as you have a caldav server (Google, Yahoo, Custom), you can already sync your events and tasks with the firefox os calendar application. Contacts should work with carddav, but you need an extension to make contacts work with carddav in Thunderbird.