If you want to talk authentic "Grunge," then Mudhoney, Nirvana and their ilk are what you're looking for.

While lyrically more "honest" and "darker," AiC came out of the hair metal scene (musically) and never really totally left it behind. And forget about finding a Grunge band with harmonies like that.

But, as has been said; pretty much everybody who came out of Seattle at that time got slapped with the Grunge label, accurate or not.