I think Ellen will do a great job. I liked her judging stint on SYTYCD. She got on my nerves a little bit with the way she kept straying off topic and some of her jokes got old really fast, however, she forever won me over with how quick she was to defend Evan when Nigel was so cruel to him.
She will bring a more "common" person voice to the panel and will say what we are all thinking at home, she's already shown that she isn't afraid to go against the herd, and I foresee her calling Simon and the others on their bull frequently.
Bonus....in a season of rambling comments and DAWGS that was HAWT!...it will be nice to have a coherent person on the panel. Plus her smile makes me smile, hope she smiles often.