Would you like to become a demon and be around sexy girls...?
Of course you can't but this gives you a little taste about it.
Explaining the story to you is much more harder than to explain the meaning of "Synecdoche, New York". Why? Because it's really hard to keep up with. Of course, you can remember most of the plot points etc. but the overall story is so confusing that you have to at least watch it twice before you can even understand it. The story is so fucking awful and confusing, that it makes a great "so bad that it's good"-anime.
The art style isn't really any different from any NON-SERIOUS (anime that is mostly fan-service) anime but I have to give some credit about the action scenes which were pretty well done.
Alright music, good voice acting... yeah.
Of course, the characters are over the top. This anime has probably the most popular waifu material out there, Rias, Akeno, Koneko, Asia etc. All of these characters are fun to watch. I do hate Issei but at least I can write my own fan-fic where Issei is replaced with Irishman.
A bad anime that you can just laugh at it's ridiculousness. Seriously, this anime is a goldmine at that.
It's a bad anime, but you can have a great time while watching it. Of course, don't watch it while your parents are home. If you are alone and want to watch this anime, here's a tip how to watch this and have a great time: #1 get drunk or high, #2 invite some of your friends that make fun of anime... or just don't.