440C 440C 440C 440C definitely.
I like 440C because it is tough very stainless ,takes a wicked polish and gives a great cost versus performance ratio. 440C was originally designed for jet engine rotors. It is cheaper than the high end steels mostly because it is made in much larger quantities. Also it is well established how to get the most out of the heat treat.

The AAS is an awesome piece of infi because it is a size you can carry with you daily. I usually carry my beloved SS4 in my pack because the handle is to thick for my pants. An AAS with the skelly handle and a pocket shaped sheath with a clip would be as handy as a folder.