Nice example! I prefer autoflush because the intent is much clearer than messing with the $| global variable.

As an aside, it's a shame Perl was originally released with so many evil global variables because by the time lexical file handles made it into Perl 5.6 a host of unfortunate idioms were in common use, such as:

select((select(FH), $|=1)[0]);
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Of course, such old coding horrors like this can be expressed more clearly nowadays with a lexical file handle (see also):

use IO::Handle;    # update: not needed for Perl 5.14+
# ...
$fh->autoflush();
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For more examples of historic interface design boo-boos, see the Some Examples of Interface Mistakes section at: On Interfaces and APIs