It's alright. In the beginning it's very fanservice-y which was really the only selling point, but as it develops, the cliches kind of slowly melt away and you get a decent story with less predictable moments. I started off rating this pretty poorly, but I feel like I was wrong and can rate this a tiny bit better. This action and art are still pretty great and the MC finally finds a goal beyond the kind of boring one he had at the start. It's still not an amazing manga, and it's still full of cliches and fanservice, but it's not terrible. It's also pretty unique as far as "demons vs. the world" plots go.
I give it 7/10 instead of the original 6. I first said it's good for when you want to just enjoy how something "looks" and not get invested in anything, but I found myself slowly sinking into it and beginning to like the characters.