Hey sloth, I have the rucki on pre-order. I don't think they've shipped yet.
Daniel's S7 Waki is longer, and looks like it's more weight-biased towards the tip. As for SR-101 vs S7, it's a close call with the advantage to SR-101 for edge retention I think. But if Daniel's S7 HT comes out with results like Scrapyard's SR77, then nothing out there would be tougher unless you venture into exotic territory (my grail steel is Vanadis 4E, but might as well be unobtainium). However, I think the key to bringing S7's performance over the top might be to bring its HRC above 56-57 (tool steel applications) and bring it to 58-59. Might even get away with it when you take Daniel's grinds and blade geometry into consideration. That extra point or two in hardness makes a big difference for the S-series steels (only academically speaking, I have never worked with steel) from what I've read up on. All in all, S7 is about as good as you can get for custom big blades/choppers, realistically speaking. There's CPM-REX121 and Vanadis 4E that would would surpass its properties, and those are extremely exotic having workable hardness at 66+ (Vanadis4E) and 68+(REX121), but they are also very hard to get, expensive, and near impossible to find someone to work with it (I'm getting one of Farid's CPM-REX121 folders

). I think the DFK S7 waki will be great, as will his other big S7 blades.
I'll rely on a knifemaker's skill to make a good steel excel, which is what I'm expecting from Daniel.