I dind't find it particularly good, as Whyte Lyon wrote IMO the lacks character, and not much happens, especially if you already read the two characters' backgrounds. But I did like how Rengar describes Kha as something otherworldy and wrong (especially the part where he says even the air refuses to touch it :D). It's not badly written, it's just that this kind of story isn't the kind of story I appreciate, I'm more for characters and internal struggles :)
Do you usually read league's lore or did you just happen to read only this story? If so, if you explain what you liked, we could suggest other stories on universe that you could enjoy :)
"Silence for the damned" and "The eye in the abyss" are two of my favourite stories out there :)