The V3m is identical to its V3c counterpart, except for two new features: music playback and a MicroSD expansion slot for music and video. This solves the memory limitation issue the RAZR was having.
Fans of the Motorola RAZR may want to get a hold of this version instead of the V3c. It is expected shortly on Verizon.
Source: Getting to know the RAZR V3m