Ok, so I've caught up with the latest chapter (66), and all I can say about this book so far is that it's really good. Ok let's start from the top.
Writing Quality: I think that the writing quality is really good. The author knows how to build suspense, knows how to write fluff, knows how to make the humans, feel... human? which is a very significant thing. And the author claims that they're not a native English speaker, but... the grammar and writing quality is as good as a native English speaker so don't let that deter you.
Stability of Updates: 1 chapter per day, feels short probably because I really like this book, but I mean, you can read ahead (10 chaps), but still, 1 chap a day already happy with that, at least not one per week.
Story Development: In terms of story development, think it's a tad bit slow, don't really mind though because at least it's entertaining and builds suspense. Lots of suspense. Can't wait to see the puzzle pieces come into place. And also the girls are really cute. That's a plus too. :D
Character Design: Already said, they feel like actual humans, that do human things, sometimes irrational and sometimes rational, emotional, etc. Sooo, already more than I could ask for from a book.
World Background: Finally, world background. It's pretty well-developed considering it's only 66 chapters in, and I think there's a lot of room for it to expand.
Conclusion: Give the book a try, I think you might enjoy it :D