rlm_perl , unlang and Exec-Wait with Perl

Hi, How could one compare between Rlm_perl and Unlang(or any other relevant module) for performance. I've read in http://wiki.freeradius.org/index.php/Rlm_perl that rlm_perl supports muliple instances and threads allowing faster processing. How is it with policies done using unlang? ......Faster, slower or no significant diff? As described in the same site 'Exec-Program-Wait' with perl scripts is slower than rlm_perl. Would like to have a clearer view about these points. Thanks, rg