From what I can tell they all use the same atomizer head so they must be essentially the same thing. I personally only have experience with the MT3 which is just a T3 with the metal outer case, so same volume and size I would guess. The EVOD looks like it is just an MT3 with smaller capacity (totally unconfirmed and they appear to be the relatively the same size) and the head resistance is 1.8ohm. Head resistance for the T3 and MT3 is 2.4-2.6ohm, I'm assuming there are replaceable heads specifically for the EVOD with 1.8ohm resistance but I haven't seen them. Experts, please correct me if I'm wrong.