I'll just post the summary output from cmpthese: (perl 5.6.1)

              Rate for_array      grep       for  grep_two
for_array  82736/s        --       -8%      -12%      -44%
grep       90290/s        9%        --       -4%      -39%
for        94074/s       14%        4%        --      -37%
grep_two  148846/s       80%       65%       58%        --