Dorinda and Rinna are both great housewives for sure, but I give the edge to Dorinda. She had plenty of huge moments this season (mostly in the first half with all of the John drama), and her "I made it nice" comment is probably the most memorable line of the season. And yea, she somehow manages to stay likable despite being a drunk and a big pot stirrer
Meanwhile, Rinna really annoyed me by the end of last season-- it wasn't even necessarily her fault (they ALL annoyed me by the end of last season). She's still great tv though.
I think Erika has a chance to add her name to the "greatest additions" list if she's willing to put in a little more effort next season. She has an incredible presence and hilarious delivery, but she needs to get into the drama more. We saw flashes (like her SCREAMING on Yolanda's behalf at that dinner party), so she's obviously capable of dishing it out. I'd also like to hear a little more about her personal story/relationship-- if she's willing to give it, she'd definitely be up there.