Currently, the CDT3-MkII is the flagship, using remaining stock of the CDPro2 LF mechanics and an on-board Rubidium clock. Because Philips stopped production of the CDPro2 LF, the CDT2-MkII as built on their CDM4 mechanism [right] will be the model going forward.
You can check it out on the 6moons.com review.
The more expensive CDT3 still uses the Pro 2 unit.
All the best,
Nonoise