How do you differentiate between tabs that the logger generates, and tabs inside log messages? You need to escape the tabs inside messages. This problem exists with any character delimited format (e.g. csv).
In fact, they compress to about a 3% of their size. Since they really only exist in text file form for a limited period of time before being moved on to a separate logging system, their exploded size isn't much of a concern.
I don't understand this? A tab is a tab?
> JSON
Downside: File size. If you have any appreciable level of traffic/activity this matters.