The Halcyon ballast housing is carefully machined to allow ample room for mounting screws and is 0-ring sealed, notably reducing the likelihood of water intrusion.
The competitor's rear ballast housing is roughly constructed with mounting holes that near (and sometimes may) penetrate the housing. In this case the competition does not use an o-ring seal.
Note: Close inspection reveals a bulge in the competitor's ballast housing; the mounting screws nearly penetrate the housing.
The competition's rough belt sander finish (above) is debatably relevant. However, divers investing thousands of dollars and relying on this equipment as life support might prefer greater attention to detail (below).