Firefight is better than the Warzone version!
Eh, maybe you could modify the settings, but you're still playing Firefight with Reach's sandbox. WZ FF leans more on the WZ side of things than I'd prefer (I'd love an ODST-styled survival setup with limited lives but the REQ system added onto it) but I've had more fun playing WZFF than I ever did with Reach, which mostly turned into "oh boy everyone's gonna' play Arcadefight to grind commendations."