Symantec IPS vs Appliance IPS

Is the SEP IPS an appropriate substitute for an appliance based IPS? PCI DSS compliance states that all access to payment card infrastructure be secured by an IPS at the perimeter of the network. We don't need to be PCI compliant, but we're using those standards as security guidelines. If we have SEP IPS installed on all devices in our production network, would that satisfy that requirement?

I've looked at the signatures in the Endpoint Manager and it certainly doesn't look like the several thousands of signatures that Alert Logic and Cisco boast. Is there more going on behind the scenes then is obvious through the Endpoint Manager Configuration?

Thanks for any input,