The Seasonic Prime TX-1600 ATX 3.1 wins in 6 out of 9 comparable specs, with 2 ties. Its biggest advantage is PCIe Connectors (233% better).
RM750e wins in 1 spec (MSRP: 80% better).
Recommendation
Choose Prime TX-1600 ATX 3.1 if you want the best overall performance — especially pcie connectors.
Choose RM750e if msrp matters more to you.