SpamHaus DROP list

[Alex Neuman van der Hans]

Anybody here had any success/horror stories regarding the implementation 
of the SpamHaus DROP list? I've been getting a lot of crap (spam and 
other assorted network nonsense) from places in the DROP list and I'd 
like to know if it's worth implementing at the firewall level. Any info 
on false positives would be good too, specially if there are any 
otherwise legit servers in that "rough network neighborhood".