No major difference. SRN is basically an ultra-Christian version of Fox News.
Scary, I know.
It's no secret that Salem Broadcasting is a Christian based network. Below is what they post on their web site.
Salem is a leading U.S. radio broadcaster, Internet content provider, and magazine and book publisher targeting audiences interested in Christian and family-themed content and conservative values. In addition to its radio properties, Salem owns Salem Radio Network®, which syndicates talk, news and music programming to approximately 2,000 affiliates; Salem Radio Representatives™, a national radio advertising sales force; Salem Web Network™, a leading Internet provider of Christian content and online streaming; and Salem Publishing™, a leading publisher of Christian-themed magazines. The company owns and operates approximately 100 radio stations, including stations in 23 of the top 25 markets.
So if hearing a Christian perspective isn't YOUR cup of tea, then use the station selector and tune in one of the many non-Christian oriented stations that serves Philly. There's nothing wrong with a station that offers a perspective for a specific demo, which actually is what all radio stations do. WNTP and WFIL are Salem stations so you know right off that their perspective will be from a Christian perspective. WNTP actually aims at a Judeao/Christian perspective as a couple of their talk hosts are conservative Jews (Prager and Medved).
900 AM in Philly, forget the calls aims at a urban minority audience. B-101 aims at females, WIP and the Fanatic 97.5 aim at men, WHYY-FM aims at liberals and intellectuals, WPHT aims at rightwing conservatives, etc, etc.