I'd say she's definitely worth coming to see. I saw this play on Saturday night & she has an Act 2 aria (of sorts) that had people cheering. The Times called her performance a "tour-de-force" in their review: http://theater2.nytimes.com/2007/06/18/theater/reviews/18tosc.html?ref=theater
I did and I went to get tix for a friend coming into town. FYI - it's 2-for-1 $65 ticket, NOT 2-for-1 $39.50 ticket. It's still a good deal, just not as good as I thought it was going to be.