The Zeus ZM1200M is the pinnacle of what SilverStone currently has to offer. SilverStone markets the Zeus as a workstation unit, something quite strange for a fully modular PSU, but with four 1200W units among their ranks it is understandable that SilverStone is trying to categorize them.
The Zeus ZM1200M is not a revamped version of the Decathlon DA1200 unit; its an entirely different design down to the core. It is also one of the very few PSUs which have six 12V lines, but it also has the ability to merge all six lines into one, manually.