If you are returning a simple, short list of values, or even a hash, returning the values is probably the best, because it is the simplest.

However,

   my @values = f(...);        # simple read,
                               # @values is a copy
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or

   my %hash = f(...);          # hash is also a copy
   my $value = $hash{'value'};
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makes a copy of all values, so if you return a lot of values, you might have some performance issues. In that cast, a reference might be faster.

If you want to return more than one array or arrays and hashes where the returned lengths are unknown, references are your only choice:

   my (@v1, @v2) = f(...);
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makes @v1 slurp all return values, leaving @v2 empty. Solution, with a few comments:

   sub f {
      (...)
      return \@v1, \@v2, \%v3; # return 2 array and a hash
                               # reference
   }

   my ($ar1, $ar2, $hr3) = f(); # collect references
   my @ar1 = @{ $ar1 };         # get the first array,
                                # creating a duplicate
   
   foreach (@ {$ar2} ) {...}    # avoid copying the array,
                                # probably more efficient

   my $value = $hr3->{'value'}  # some people find this
                                # notation cumbersome
                                # and avoid references
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