I saw it last night and thought it was very good. However, to my ear, Redgrave did have problems with a few of her lines. The mistakes weren't that serious, but I imagine her performance will get even stronger in the coming weeks.
Since Redgrave plays a non-English speaker who admits to having trouble with the language I felt that some of the "stumbles" were actually well-timed character choices.
Marie: Don't be in such a hurry about that pretty little chippy in Frisco.
Tony: Eh, she's a no chip!