You are being unfair to map.

#!/usr/bin/perl -w
use Benchmark;
use strict;

my $count = shift || -3 ;  # set the test counter
my @array;

#load up an array of crap
push @array, rand(256) for 1 .. 1000;

open NULL, ">/dev/null" or die $!;
timethese (
    $count,
    {
        'join'      => \&print_join,
        'map'       => \&print_map,
        'list map'  => \&print_map_list,
        'field sep' => \&print_field,
        'for'       => \&print_for
    }
);

# use join to print each array elemnet.
sub print_join {
    print NULL join("\n", @array);
}

# use map to print each array elemnt,
sub print_map {
    print NULL map{ $_ .= "\n"}  @array;
}

# same but a no concat
sub print_map_list {
    print NULL map { ($_, "\n") } @array;
}

# use map to print each array elemnt,
sub print_field {
    local $, = "\n";
    print NULL @array;
}

# use a loop.
sub print_for {
    print NULL $_, "\n" for @array;
}
[download]

Yields:

Benchmark: running field sep, for, join, list map, map, each for at least 9 CPU seconds...
 field sep: 11 wallclock secs ( 9.60 usr +  0.05 sys =  9.65 CPU) @ 1121.04/s (n=10818)

       for: 11 wallclock secs ( 9.28 usr +  0.02 sys =  9.30 CPU) @ 621.40/s (n=5779)
      join: 11 wallclock secs ( 9.20 usr +  0.02 sys =  9.22 CPU) @ 2888.07/s (n=26628)
  list map: 11 wallclock secs ( 9.07 usr +  0.04 sys =  9.11 CPU) @ 268.94/s (n=2450)
       map: 32 wallclock secs (26.02 usr +  0.26 sys = 26.28 CPU) @ 57.95/s (n=1523)

What happened with your field sep test? I can't get it as fast as you claim it to be. You should also note that join does not put a newline after the final item.

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