I have owned many Gerber knives over the years and have never had any complaints. Everything from folders and clip knives to fixed blades. At one point I owned a MKII but was young and silly and sold it. Nice knife, but very specialized in its applications. The design is based loosely on the Fairbairn-Sykes commando dagger from WWII. The MKII was very popular during the Viet Nam war.
The Gerber is made of 400 series stainless steel with a 7.5 inch blade and has an aluminum grip. Sheath is usually heavy nylon. Sells for about $80. Recently, what seems to be an OK substitute came to my attention: A 7.5 inch blade of 400 series steel with a textured TPE-wrapped grip, the Schrade SCHF44LS. Leather sheath included and sells for about $20.
As I have said, the steels are both about the same 400 series, though Schrade calls theirs 7Cr17MoV. Total length of either knife is a little over 12 inches. For some reason (possibly heavy drinking or drug use) Schrade calls this a “Needle Boot Knife” and the leather sheath has a steel belt/boot clip. Seriously, you want a foot long blade on/in your boot? Maybe if Bigfoot wore boots, but not your average Joe. I wear a size 12 (sometimes 13) and calling this a boot knife is ludicrous. However, for the price it compares favorably to the Gerber.
As to the differences in steel, it must be cautioned that even though the chemical composition of the steel is similar or even identical, each manufacturer has different hardening and tempering processes that could make the steel act completely differently to sharpening and stresses.