I got spyderco knives with FRN, G-10, steel, CF.
FRN works well but looks ugly. No one will ever say FRN looks nice beside steel, G-10 or CF.
FRN is light, and FRN spydies are strong and reliable.
The steel spydies are the same price as FRN, but you must really get the most recent steel ones. The earlier steel ones gave me some probs, with the mating between lock-bar and blade. I have not had this problem with the more recent steel ones.
Steel is strong but slippery. It also scratches up easy. The steel spydies don't have VG-10 or ATS-55 for the endura and delica. They use softer steel.
Also the serration pattern for the earlier steel ones has the serrations going right up to the tip, weakening it. The later ones corrected this.
To me, steel looks better than FRN.
The spydie locks with FRN are probably the best out there. For FRN, I ONLY use spydies. No other brand I trust for FRN. Other brands I use the high-end ones, but for low-cost FRN, I ONLY TRUST spydie.