Just two main things to consider with Peerguardian. (1) It uses a lot of computer resources (on some people's systems at least). (2) PG do not recheck their ip addresses after adding. And since so many spammers use dynamic ip addresses, which can change quickly in some cases ... means some innocent people could & as has been told privately to me .. have been affected by PG's filtering with their own ip's on the list.

People in general do however find great improvement in using PG combined with LW. Just that some innocent people might get affected by its use.