This audio recording is from her 1997 Mozart Arias recital disc with Colin Davis conducting. She makes Vitellia sound angry, desperate, and yes, at one point even a bit tired. Imagine what Frau Kasarova could do with this on stage (and with Maestro Harnoncourt conducting!) Add her to the list of Sestos I'd love to see move over to Vitellia!
I, for one, would like to see her in a few more girl's roles (even though, I think we all agree that she's an awesome Mezzo in Pants!)