This is one of the nicest monasteries in Greece. It is an orthodox one created a few centuries ago.
It is mainly famous for the icon of Virgin Mary which was brought from Proussa from which the monastery and the near village is named after.
Personally I believe that the best thing there is the scenery and the "energy" of the place. Thus, this is a must no matter what you believe in (christian, not christian, atheist etc).
It takes around 30-45 minutes from Karpenisi by car. There is a local bus taking you there once or twice every day depending on the period.
Watch out! Especially the winter period due to rain/snow sometimes the road is a bit dangerous that's why it is advisable to ask at you hotel/hostel to check if there are any problems before you go.
On your way there the scenery is also beautiful and during the summer months there are some outdoors activities running around there.
Best season to visit it: April-mid July cause the road is safe, the scenery is spectacular and there are not sooo many people as in August (during which the monastery is full with tourists.)
After visiting it don't miss the chance to visit one of the local small cafes or restaurants to eat one of the local specialties. My personal favorite are the sausages made by "Strimmenos".
Last but not least if you enjoy walking it is a custom for people to walk from Karpenisi to the monastery before its big celebration. It will take you around 4-5 hours (including stops) to get there.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.