use Benchmark qw(:all) ;

my $value = 'FALSE';
my $count = 1_000_000;

cmpthese($count, {
                  'regex' => sub { $value =~ /^true$/i },
                  'eq'    => sub { lc $value eq "true" },
                  'index' => sub { index( lc $value, "true" ) >= 0 },
                 });