A disaster called Space-quake appears in the Eurasia and kills 150 million people. 30 years after that, The peaceful life of Itsuka Shido is going to change after he meets the cause of those disasters, a Spirit. Then, he learns that the only way to stop a Spirit is by dating her.
Now that we're more familiar with the story, let me give you some reasons to watch/read it. Most of the points below are based on the Light Novel, as the Anime is just an adaptation and it doesn't contain the levels of detail that the Light Novel has. However, the Anime is great.
1. It has a really interesting story, it has many elements from a lot genres, so it's perfectly suited for all kinds of tastes. It manages itself to be enjoyed by many different types of people. It's a really fun watch either if you are into battleharems or not.
2. The characters are really charming and you get fond of them quickly, they grow in your heart as you watch them. There's no bad character in this story as they all have an important role and a purpose that feels made for them.
3. Shido is an excellent Protagonist, he's not dense or extremely horny. The man tries to understand the problems of the people he loves and helps to overcome them, he has a heart of gold and he really doesn't like to play around. He really stands above many other protagonists.
4. It has some of the best Foreshadowings in fiction. The author gives clues of really important events since the very beginning of the Story, and you don't catch them until you're done with it and rewatch the parts you didn't catch on your first watch.
5. Shido has a real reason to make the Spirits fall in love with him, and he needs to give all of his efforts to open their hearts because he wants to save them from being killed, and also wants he to give them a new chance to live a better life, and show them the beautiful world
6. All the Spirits are different from each other, they have charming personalities that are nice too see and appreciate. There isn't really just one best girl because every girl is a best girl, and they unique in their own way.
7. It has one of the most unique power systems in all the genre. The Angels, Special techniques, weapons, and Astral Dresses are named after religious figures and other aspects from the different mythologies and religions, from the Kabbalah Tree of life to the Norse and Arthurian
8. Even though it has some Fanservice included, it doesn't ruin important moments of the Story, or it's overused to point it's annoying. It blends nicely with the story and works perfectly used in most of the cases.
9. It covers serious topics like the lack of Self-esteem and how people hides their insecurities under a disguise, the importance of family bonds, how loneliness can affect the way people see the world, overcoming past traumatic experiences, and how people refuses to be saved.
10. It's more than just a battleharem series, it hiddes a mind-blowing story behind the stage with some Plot-twists that will shock you and let you thinking about it for a while. This story is really misunderstood and often judged because it's looked just at the surface of it.
Now that we are done, I hope this helped to clear your mind about your doubts about the series and start watching/reading this amazing wild ride that Tachibana Koushi wrote to be enjoyed. Don't let others decide what you will think about it and experience this series for yourself
Here's a welcome gift that contains basically everything that you need to enter the Franchise (The Anime, and the Light Novels, also watch the Director's Cut version for the Anime because it contains more material). Courtesy of a friend of mine. https://drive.google.com/folderview?id=162rNSStjoD96cw3teN-ZWA4h_o7So21V