Pros:
It's cleaner. Less visual noise. More elegant.
Cons:
The big one: Can't use newline. This is the only thing that I don't like about SASS. See example below.
The rest: Higher barrier to entry for people who struggle with the apparently difficult concept of indentation.
In SASS you are forced to stick to lines. So if you have
@function -create-gradient-from-color($bgcolor:#000,$depth:6%)
...code...
then you can't do this, which i find much cleaner
@function -create-gradient-from-color(
$bgcolor: #000,
$depth: 6%
)
...code...
That will throw an error because of the newlines.
But you can do that in SCSS, since it doesn't care about newlines
@function -create-gradient-from-color(
$bgcolor: #000,
$depth: 6%
) {
...code...
}
So I find myself keeping things terse in optional argument strings to prevent this situation.