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.

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.