incrediBILL - 7:23 pm on Nov 21, 2010 (gmt 0)
No, it hasn't hurt my site performance or caused member outrage whatsoever.
If it did cause member outrage, I'd probably tell them to go read the spam elsewhere.
I also require email validation on all accounts and those that don't validate their email accounts are automatically purged in 5 days.
A few years back I was overrun with spammers and spamming attempts until I implemented this.
Today I have none, zero, nada.
They simply gave up, no trace of spam attempts in the log files, nothing.