The Gigabyte Z890 AORUS MASTER wins in 6 out of 14 comparable specs, with 7 ties. Its biggest advantage is PCIe x1 Slots (100% better).
MAG X870 TOMAHAWK WIFI wins in 1 spec (MSRP: 42% better).
Recommendation
Choose Z890 AORUS MASTER if you want the best overall performance — especially pcie x1 slots.
Choose MAG X870 TOMAHAWK WIFI if msrp matters more to you.