One can see there are a lot of churches in every city and most of the Romanians are still religious and go to church on Sunday. However, religion is often considered a personal matter of which you would not usually talk.
The differences between the Orthodox and Catholic church are not big, both religions being Christian and having a lot of similarities. The Orthodox traditions have influenced a lot the Romanian culture and traditions.
However, there are other religions in Romania too, such as Catholic, Greek-Catholic (a religion that combines Orthodox and Catholic traditions, found mostly in Transilvania and in parts of Ukraine), Protestant, Muslim and Jewish.
Furthermore in almost all the Transilvanian cities, the main square of the city would include an Orthodox church, a Catholic one, a Greek-Catholic or a Protestant one and sometimes even a synagogue.