Since my HRC testing of the Delica, I have used it on various materials. I haven't gotten crazy with it, but I haven't babied it during use either. I have pushed it a bit, within reason for a 2.5mm thick blade, to test edge stability. Very thick shipping cardboard, a cloth backed rubber material where I work, and even through some hard tote plastic. These coupled with everyday use cutting, it is performing VERY well. The heat treat seems to be spot on. Edge holding as expected from k390 at that hardness, but the toughness is suprising! I even ran the factory edge for a while. I am on the third edge, and I am using normally as a fantastic slicer and edc.
I plan on getting the Endura k390 within the next few weeks. I assume it will be a similar HRC and performer, but I will post the test results in the HRC database.
Great work on the heat treat Spyderco!