Difference between these two nginx try_files statements for WordPress?

As far as I know, WordPress does not require a q= parameter set to the original request (the pretty permalink). So in the second option, the q= parameter will be silently ignored.

According to the Nginx wiki page for WordPress, the query parameters (?$args or $is_args$args) are included:

… so non-default permalinks doesn’t break when using query string

I do not know what “non-default permalinks” are, but I just use the following, which works fine with pretty permalinks:

try_files $uri $uri/ /index.php;