Except map is painfully slow in void context:

use strict;
use warnings;

use Benchmark qw( cmpthese );

my @list = map { '' . int(rand(100)) } 1..1000;

sub map_test {
   my %counts = ();
   map { ++$counts{$_} } @list;
   1;
}

sub foreach_test {
   my %counts = ();
   ++$counts{$_} for @list;
   1;
}

cmpthese(-3, {
   map     => \&map_test,
   foreach => \&foreach_test,
});
[download]

This is perl, v5.6.1 built for MSWin32-x86-multi-thread

          Rate     map foreach
map      953/s      --    -25%
foreach 1278/s     34%      --
[download]

This is perl, v5.8.0 built for MSWin32-x86-multi-thread

          Rate     map foreach
map     1705/s      --    -25%
foreach 2288/s     34%      --
[download]

This is perl, v5.8.0 built for i386-freebsd

          Rate     map foreach
map      847/s      --    -29%
foreach 1190/s     40%      --
[download]

This may have been fixed since.