I saw this evening's performance. I thought Bennett was excellent as Penelope -- the best aspect of a uneven production.
I agree with an earlier post suggesting that Act I played largely as an over-extended set-up to Act II, which often seemed like a series of cabaret numbers. However, I think that may have more to do with this particular production than with any inherent weakness in the show itself.
Also, I think that even if a person is familiar with the underlying mythology, the storytelling was at times unnecessarily confusing. For instance, they could have easily made it more clear visually that, during the Act I bake-off, one of the female contestants was offering Helen to Paris as a bribe. As it was, until the long sequence was nearly over, I thought the contestant was only offering herself, with numerous suggestive gestures involving her own body, coupled with references to her "pie," etc. As a result, what should have been giving momentum to the plot instead played mostly as a mildly entertaining digression.
Anyway, I'm glad I saw the show, but I can easily imagine a sharper, more coherent production, even within the context of Encores!