Rated 3 out of 5 stars

Decent enough product.
I've yet to find a way to subscribe to shared folders or shared calenders though, so somewhat middling.

This review is for a previous version of the add-on ( 

Neither shared folders nor shared calendars are promised features. Please see the feature description here and on https://www.beonex.com/owl/ for the expected feature set.

Tip: For shared folders, go to OWA, add the folder there, and restart Thunderbird.