Rate question

[Jeff]

I've seen an installation where postfix handed off mail directly to 
spamd, treating it as a policy server in smtpd_recipient_restrictions.  
I was thinking about doing this for a server with several thousand users 
and heavy usage. In that configuration, how would spamd behave under 
load? Is it likely to cause problems? Should I be using amavis? What's 
the best way to get mail to spamd when the volume is high?