I was a bit unsure about to watch this or not, since it is a shoujo, but I found out that it's okay for guys to watch too. It's not typical shoujo either.
Story
A lot of girls in a religious school, and their relationships. This could have resulted in something mediocre, but I think that it was excellently executed in Maria-sama. Many episodes were single standing, telling about the past or the present of the girl, and when there were follow-up episodes, I just had to watch on. Great story, almost bordering to slice of life, but it's a bit too dramatic to be considered that. I also liked the Yamayurikai (kind of student council), which was quite unique.
Art
This is maybe the shows weakest point (at least in my eyes), not that it affected me too much. There's mostly boring colours, and the animation don't seem too detailed. Character designs were good though
Sound
Background music consisted mostly of classical, a bit too classical for me, but it worked well. It fit well into the general mood of this anime. Neither opening or ending themes were that good either. But the voice actors were great.
Character
This is a very character-driven anime, so thankfully the characters were good, and the relationships were interesting. I liked all of them, but there could have been a bit more focus on Sachiko and Yumi, which were my favourites. But the support characters were good as well, so the result turned out great. The relationship between Sachiko and Yumi is the most important, and they are also the most interesting (and funny)
Enjoyment
Yeah, well, I loved this series. Something abut it all made me love it. I got pulled into the story and the relationships, and enjoyed every episode. Since it's aimed for girls, there wasn't any fanservice or moe-characters, which I found refreshing.
Overall
A truly great anime. Felt very refreshing, with great story and characters. A recommended watch (unless you're only into action).
9 / 10