I think it all depends. Most people perfer the upstairs--I perfer the downstairs becuase the chances of getting an empty seat next to you are greater and luggage storage is not such an issue.
I think all of the 747's will have the NBC by this summer.
Even though the 747 has a bit more room to walk around in, the forward business cabin in the 34c only has two rows and this makes a great place to sit--much better than the upstairs of the 744.