I have been using Vista 64 Ultimate on my desktop for a year. Although it
took a couple of months in the beginning, all hardware and drivers work
fine.
I installed it on my Asus tablet, and I use it fine. Asus has refused to
write new 64 bit drivers, however they had some in the beginning. On this
device the hardware button to rotate the screen does not work, but Vista
will rotate it for me.
As a rule, new operating systems are conceptualized 5 years before RTM.
While I do not think hardware manufacturers should not jump on that early,
at two thirds of the way they are plain STUPID not to get involved. Good or
bad, an OS is going to launch when that much time is spent on it.
My 2 cents