I saw that one when it was in Brooklyn. The small prints and personal work were ok. The big stuff was, well, the big stuff. Nice if you're impressed by eye-candy, not much there to elicit a strong emotion.
I expect it could be a bit of a mixed bag but I'll definitely try to see it - and I've never seen anything of hers 'in person'. It'll have to take second place behind the Rothko exhibition though! (Tate Modern) which I haven't yet managed to get to yet (still time though - it's on til Feb '09). My intentions to visit exhibitions seem to have got a bit derailed recently but there's plenty out there!
I'll definitely pop in to see the Liebovitz exhibition. I went to see Rothko last weekend and the crowds were simply horrendous - it's impossible to stand back and consider the pictures when it's so busy. I'm going to wait a bit and then go back one evening.