The NZXT C1500 Platinum wins in 6 out of 9 comparable specs, with 2 ties. Its biggest advantage is PCIe Connectors (300% better).
Focus GX-650 wins in 1 spec (MSRP: 76% better).
Recommendation
Choose C1500 Platinum if you want the best overall performance — especially pcie connectors.
Choose Focus GX-650 if msrp matters more to you.