I feel that reviews don't play as big a part as they once did. I think that this like message boards and word of mouth play a big part.
If reviews were the make and break of a show then something like Wicked wouldn't be open.
Keep in mind that Wicked was on TKTS during previews as were a lot of shows that turned out to be hits.
I think its hard to tell what will be a hit and what won't. It is all a shot in the dark most of the time. As I said there are some shows that have been doing great ine previews that do continue to do great when the show opens.
"If you try to shag my husband while I am still alive, I will shove the art of motorcycle maintenance up your rancid little Cu**. That's a good dear"
Tom Stoppard's Rock N Roll