Dunno if anyone has caught this, but Preston is releasing a new MDR, the MDR3 (not the same as the MDR-3D). Nothing yet on the Preston site, but there's an article in FDTimes.
A few new features such as analog input for zoom control (a request from steadi ops) and a fourth channel. Higher current throughput to the motors it sounds like, for higher motor speeds and torque. A little less chunky than the MDR2 but the weight isn't significantly less; just denser.
Immediate impression is that the placement of the antenna looks a bit inconvenient.