I would go with the Blackbird SK-5, and here is why. 1) Good warranty. Ontario stands behind their products. 2) Fallkniven S1 hides the tang in a rubber handle, but it pokes out at the butt of the handle.You cannot see the sides of the tang though, and the rubber handle cannot be removed.The Blackbird SK-5 uses Micarta scales with a exposed tang that can be removed; No brainer. 3) VG-10 is a good stainless, but 154cm is tougher and will sharpen easier in the field. VG-10 has better corrosion resistance however, and it will have better edge retention. 154cm is as tough as S30V, and both of these knives are almost as tough as 1095, yet their corrosion resistance is so much better.VG-10 is great stainless though, and it makes a good steel for a pocket folder.Here is a steel chart for anyone that wishes to dispute my claims on the steel.
http://bladereviews.com/knife-faqs/knife-steel/
P.S Blackbird SK-5 WILL strike a firesteel VERY well with its 90 degree spine, in fact it will shower sparks.