From what I understand, SR-101 has super lateral strength and SR-77 has super and then some lateral strength.
SR-77 holds a good edge but SR-101 holds a great edge.

All in all I would consider SR-101 a superior steel, since the great edge holding of the SR-101 is more important than having a little less lateral strength.
Technical differences...? I dunno.

Having only one pancake, leaves more room for bacon!

JYD#174

"Rasmutt"