TPU, I just picked up a couple last week at a local boyscout store. $2.30 each.
ACMarina, the artificial flints do not need steel to strike against. In true flint and steel, itis the steel itself that is shaved off and makes a spark. In the artificial flints like the boyscout model and those attached to the mag bars, all it needs is something hard and sharp enough to scrape off some of the "flint" because it is just the mechanical action of breaking off tiny parts fast that causes it to spark off.
GigOne, there are several tinders that are handier and even easier to use than the mag bar. To me the mag bar is real good to have as one of the alternatives, not absolutely better than most of them. The one place it is better is that it is harder to destroy. Once the steel wool rusts, it is useless as tinder. Cotton and most other fine or pre-shredded tinders can easily get too wet to light. If the mag bar is accidently dropped into the fire, you have a fair amount of time to fish it out before it is ignited (and some fires will never get hot enough to ignite a whole bar), while most other tinders and ignition sources will ignite almost before they touch the flames. I would not suggest trying this with a butane lighter or box of matches!
It is not the easiest or most convenient, but a mag bar is fairly oops-proof.
The one complaint that I have heard several times is that the flint rod can come off of the mag bar and be lost or broken. Most bar/ferocerium combo sets have the mag bar attached to the lanyard or keyring while the flint is glued into a slot in it. The boyscout hotspark is just the artificial flint and I am thinking of crafting a magnesium "key" from a slice of another bar to also attach directly to my keyring to more securely carry with it. The thinner "key" should also be easier to scrape/cut tinder from.
And all gear is inspected after returning from a trip.