I'm still constantly blown away by how flawless Eric's performances of other performer's characters are. Between Bert, Guy Smiley, Oscar and especially Grover, I just totally forget that it's not the original people performing them.
Anyway the appearance, or at least the two minutes that i've seen (it hasn't aired yet where I am) seems pretty funny. And Ellen seems to really respect the characters whenever they're on, unlike those people over on Good Morning America.