We currently run Rancid, which for a freeware program works great, but very few here, actually just me, know how it works, they just know the frontend. One thing it can't do is tell us who made a change, or when, we just know it was done in the hour previous to the last revision.
Does NCM have the ability to tell you who made the changes? Most of the devices use our Cisco ACS, which logs all connections and changes. Currently we have to look at RANCID then search the ACS logs to see who did what.