"It'll be worth it reading this book"
or
"It'll be worth reading this book"?
From what I learned in school, I will prefer the latter. But the former is one that tempts to burst out of my mind. I asked if it's natural to say the former on a language exchange app and I got serveral native speakers marking it as natural.
Are they both correct?
They are both correct.
"It'll be worth reading this book"
Personally, I prefer the above over the other mainly because it sounds more natural.
"It'll be worth it reading this book"
There's nothing grammatically wrong with this, given that it acts as an objective to reading, but it somewhat makes it a bit unnatural to read as is. In my opinion, it would have sounded natural if you wrote and read it like this:
"It'll be worth it, reading this book"
