I was right in the middle of checkout, when it occurred to me that I should check what the vendor lists for OS compatibility. It turns out that they don't specify 64-bit for Windows 7. (they do for XP and Vista)
So now even though the manufacturer may say it is, I can't order until I see that the vendor will back the product if it winds up not working.
So I sent them an email, and i'll have to wait and see what they say.