From what I understand: Firefall (MMOFPSRPG): Gear and character progression similar to other MMORPGs. Tribes Unlimited (MMOFPS): FPS style game-play similar to Planetside. No gear drops.
Also Firefall is going to be PVE/PVP focused with PvE being everyone on one side against NPCs and details for PvP are as of yet unreleased, but it seems like it will focus on Arenas and Clan vs Clan. Also Firefall is confirmed as free, though I think Hi-Rez has learned not to ask for subscription fees in that market, and it might be free as well. Firefall is more of a competitor with Global Agenda as of now I think. We will see when they release more info on PvP.