I placed a preorder on the Panasonic site. I've been back and forth between the Canons and the Panasonic, and almost got the TM300, then heard about the TM700 and that clinched the deal.
Seriously, while I'm paying extra in hopes of getting it sooner (sales tax vs none, and next day shipping), I wouldn't get the Canon just because it came out first, and I certainly decided against the Sony even though it is out first. So I think that for the folk to whom, the features and capabilities of these camcorders, matter enough, for them to pay the price, the issue of when they are available is not the deciding factor.
I'm hoping that they ship earlier than they predict, and betting that Panasonic has it before any other vendor.