The Phanteks G400A is the objective winner of this comparison, securing more individual specification victories than the NZXT H9 Flow. While both cases share several identical features, the Phanteks G400A holds a significant edge in overall value, offering a 55% advantage in MSRP. This makes it the more cost-effective choice for builders prioritizing budget efficiency while maintaining a competitive feature set across the majority of the evaluated technical categories.

Users who require extensive storage capacity should choose the NZXT H9 Flow, as it provides a 100% advantage in 2.5" drive bays compared to its competitor. Conversely, the Phanteks G400A is the superior option for those focused on maximizing their budget, as its lower MSRP provides a clear financial benefit. Selecting between these two cases depends entirely on whether your build prioritizes additional drive mounting space or a more economical initial purchase price.