What is the difference between MultiWayIf and classic guards?

What does MultiWayIf extension offer that cannot be done using | guards and vice versa?

For instance, one can write same function as

f x | x == 0 = -1
    | otherwise = x

or

f x = if | x == 0 -> -1
         | otherwise -> x

I don't see any difference between these two examples beside syntactic sugar used. Are there situations where I should prefer one over another?