First off, welcome to the forum! From what I've seen on the forums lately the older 21s pre-stamp seem to show up less frequently than the newer, stamped versions. The difference in value between them however is seemingly negligable imho. At this point at least, I really haven't noticed a significant price increase on the older 21s though many see it as enough of a selling point to include this detail in the thread title of their sale. I have read about some peoples' preference for the S30V on the older Sebs, but for every one of those there is someone who prefers S35VN. Similarily, for every person who seeks out a non-stamped Seb, there is someone who doesn't mind the stamping and can therefore purchase a more readily available stamped model. From a selling standpoint I've communicated with people who have preferences all across the board and I haven't really noticed one of these aspects in much larger demand than the other. Long term I think the non-stamped versions will be harder to come by as they are done being made for the time being. Whether or not this will significantly effect the value remains to be seen. Just a suggestion, but a poll thread may help you determine what users' preferences are concerning these variations of the Sebenza. This is of course just my opinion of what I've seen on the forums lately but I may be off. I'm curious to see what other people think about it as well. Hope this helps and again, welcome to the CRK forum and congrats on your new Sebenza, I'm sure it won't be your last.
