Six checks cover nearly every metal nosing decision. Work through them against your own step before comparing listings, because the right product is set by the stair, not by the brand.
Check 1MaterialAluminum covers most jobs. Stainless steel is for wet, coastal or heavy-use steps, and brass is chosen for appearance. The listing should say which metal, not just "metal".
Check 2FinishMill finish is raw metal. Anodised and powder-coated finishes add corrosion and wear resistance, and the listing should name which one you are getting.
Check 3Profile and leg sizeCompare the horizontal leg depth, vertical leg height and the thickness of any floor covering with your own step. Profiles vary far more than photographs suggest.
Check 4Slip resistanceGrit, ribbed and vinyl inserts behave differently underfoot. Where a rating matters, ask for the figure and the test standard behind it rather than relying on "non-slip".
Check 5Surface and fixingConcrete needs mechanical fixing, wood takes screws, and tile is usually planned before it is laid. A spalled concrete edge is patched and cured first.
Check 6ReplaceabilityInserts wear out long before the extrusion does. Check that replacement inserts are sold, or a worn strip becomes a full removal.