The big decision is are you absolutely going to see this no matter what, and you can get the seat you want right now at a discount, and it is a buzzy show that is selling well even having not opened yet? And if you're coming from out of town and don't have much flexibility and this is the show you absolutely must see, no matter what... If so, then yes, buy it.
Otherwise, wait to see if it's a train wreck, wait to see if it isn't selling well, wait to see if they held more tickets back for premium ticket holders than people who want to pay premium prices, wait to see if more scalpers bought tickets to mark up than people they can sell them to at inflated prices, etc., etc.