There are some really beautiful knives in this thread, some so rare I didn't even know existed.
Overall they are good knives that developed a group of collectors. They are clean and pay good attention to detail to make a great gentleman's folder. As for as collecting, I don't think that it really has to do with the steel. BG42 is more collectible because of the time period it was used. People like the older knives and there was less made. What's even more rare is the ATS34 in the Sebenza because that was only used in the very first numbered Sebenza.