After using detectors for over 9 years, looking for survey pins, knives, fence post that are broken off under ground and various other things for people, I would still pick the DFX for looking for evidence at a crime scene.
The detectors I have have used are the Titan 3000, Garrett 2500, AT PRO, Fisher 75 LTD 2, White's DFX, Beach hunter 300, Racer 2.