Agree with Ken
Only RBLs that are 100% reliable could be used at the Incoming MTA even you are really sure of what you do... It is recommended with MailCleaner to configure RBLs in the dedicated module (PreRBLs).
The usage of some RBLs depend of your countries, some MailCleaner users used spamcop at SMTP check without any problems and other not ... each case is different.
And it depends also of the "aggressiveness" you want to configure with your filtering gateway.