I just happened to randomly come across this question.
What's the difference between 你能看完这本书吗？and 你看得完这本书吗?
To me, they all mean can you finish reading the book, but the former uses result complement and the latter uses potential complement. I am not trying to completely revoke the idea of using potential complement, but still in some cases it just seems replaceable to me.
How do Chinese people distinguish when to use either of the two?