I still prefer Alice In Chains on the whole because it was always more accessible, not in the least because they were a natural successor to mainstream metal from the decade before. But Cobain created a sound for a new subgenre, making something that had been on the fringes more mainstream. Both incorporated deeply personal and fairly nuanced lyrics; Cobain did it to an instrumental track that was sparser, occasional discordant, and without the heavy rhythm lines that had dominated the previous decade. Trying to compare the talent of two artists, even within the same genre, is itself a trap because the creative process can demand different things from different people who otherwise share the same skillset. At the level both men were at, all artists are singular exceptional talents in their own right. Ultimately, though, Staley was mastering within the creative confines of an existing sound while Cobain was creating a new sound to go with is music.