“Going to the P25 Digital would mean that we could communicate with outside agencies, and that we would all be able to scan each others frequencies, monitoring each others activities and calls for service.”
Only if you have multi-key radios (and the coordination that goes with that), or use one standard (and less secure) encryption key.
It amazes me that they keep using the premise of interoperability to get these P25 systems funded and then encrypt them. Encryption is not interoperable without a substantial amount of coordination. They will figure this out when the big one happens and they can't talk to each other because a department from two or three counties away doesn't have the encryption key. An encrypted P25 radio system is no better than the radio system they had on September 11th, 2001.