I've never had troubles understanding Seth, but that may be because I know so many people with similar accents.
I must confess to a major lack of impartiality with regard to Seth Rudetsky, however -- even though I don't know him personally, I know his dad and stepmom. I'm REALLY hoping for the show to hit it big, even if just for their sake.
Audrey Liebross
Audrey, the Phantom Phanatic, who nonetheless would rather be Jean Valjean, who knew how to make lemonade out of lemons.