Marko, I have one of Butch Harner's little petty knives in that steel. It took me a while to get it really sharp, but it seems to stay that way. I too am curious to hear what you discover.
I would like to compare it with PM steel I am using. I might end up pass around a knife in it, so i can be compared to both XHP and CPM154. It would have to come after 52100 passaround though.
Call up Butch. Maybe he can direct you, or make a little trade.
I just used it for the first time, yesterday, and it seems really nice. Of course, it was only one use, and with the beautiful edge Butch put on, but it seems as though the edge is going to hold for a while.
I was planning to order a sheet as well. If you wanted to pitch in for a % of it, I'd be happy to share. I was quoted ~$600 for a 10x72 .100 sheet and shipping a couple months ago and I hope it hasn't changed (upwards) much since then.