I work at a clothing store where we have to cut up (make damaged/returned/washed and worn clothes unwearable and unreturnable if some one took them out of the dumpster) clothes. Today I was tasked with "damaging out" 621 items (we have to scan each barcode before destroying it).
I did a similar test using a Benchmade Vex in 8cr14mov (35 no longer shaving, @ 70 lost its working edge) and a Saber Grind Spyderco Delica in ZDP-189 (105 before no longer shaving and stopped at 200 with still a working edge).
The items to be destroyed consisted of (roughly) 40% leather, canvas or faux leather shoes (a significantly higher level of shoes compared to the ZDP-189/8Cr14 test), 15% denim and 45% polyester or cotton shirts.
This time a Spyderco Endura FFG in Superblue steel was used as well as K390 Mule Team. I started with the Endura first and made it through about 150 items however switched because I could feel the FRN handles flexing when being forced through some of the thicker shoes, at 150, the Super blue was just barely shaving. The K390 Mule then took over from 151-621 the mule was the only knife used, it started easily shaving sharp at around the at around the 450 mark (300 items in for the mule) there was no noticeable difference in sharpness from the 151 item mark, at around the 575 mark, the edge was finally have problems shaving, but could still scrap shave, there was also a slightly noticeable difference in the front/mid blade compared to the back of the blade which hadn't gotten as much use and was still as sharp as it was in the beginning. When I finished all 621 items (8 hours, and 2 small blisters later) the Mule was just barely able to scrap shave still, and still had a very useable working edge. I did notice that a few extra pounds of force was needed to cut through the thicker leather items, but it was so difficult I would have switched if I had a different knife available like I had to with the BM Vex. Needless to say I am VERY impressed with the K390's edge holding as well as surprised that it took about 5 minutes on the sharpmaker to bring back to its initial sharpness (no diamond stones used). I'll do a quick summary, though I'm not sure it means much because these blades all have different profiles and the latter two definitely had a more difficult group of media to get through.
Steel------lost shaving edge----lost working edge
8cr13mov--35 cuts---------------70 cuts
I'm definitely looking forward to/hoping for more K390 and the like (10V) from Spyderco in the future.
Also the Superblue is amazing to sharpen 7 passes on each set of stones (white and brown) brought it up to a screaming sharp edge.