[toaster] courier-pop3 vs qmail-pop3?

[Eduardo Cortés]

hi all,
what are the best one, courier or qmail pop3 daemon? system has the last 
vpopmail+mysql and qmail+toaster-0.7b3+chkusr-mysql. I see that with pop3 
daemon from courier, vpopmail logging information is not registered on logs 
with --enable-auth-logging, --enable-mysql-logging, but courier show 
information about bytes retrieved. what about performance?
Regards,
Eduardo Cortés.