Review for Provider for Exchange ActiveSync by Michal Cihelka
Rated 5 out of 5 stars
I have two outlook.com accounts. While Thunderbird's IMAP support syncs emails, this add-on (plus the related TbSync add-on) syncs calendar, tasks, and contacts. So far it's been perfect - very fast and stable.
This review is for a previous version of the add-on (1.7).To create your own collections, you must have a Mozilla Add-ons account.