They’re pretty much the same — they both insert a carriage return / line break and are both supported on DashingDon.
The main difference is [n/] can be used anywhere, even in the middle of words, while *line_break needs to be on its own line.
If I write Hello w[n/]orld it will output as:
Hello w
orld
Whereas if I use *line_break I’d need to write
Hello w
*line_break
orld
to get the same output. You can use whatever is easier for you. Though in general, it’s best to use line breaks as sparingly as possible, as they can make your game less accessible for screenreaders.
This thread has a good in-depth explanation on how whitespace works behind the scenes: