It looks like a respectable 251 of these behemoths were delivered and around 129 are now in service with Emirates having around 70% of the in-service fleet.
I know that a number of these have been parted and that market is drying up since the numbers in the active fleet are not that large and nobody wants to have a large inventory of used parts for which there is no market.
There are around 80 frames listed as "inactive", so many are presumably looking for a home.
There is no cheaper way of getting a reasonably young high capacity aircraft and floor area does count if one really intends to run a low density premium airline.
Is Global to be taken seriously?
I think that depends largely upon the depth of the pockets it has financing from. I think the math could work since many of us would love to fly in a premium class and find the upcharge for even premium economy to be ridiculous and biz is just absurd, at least for most of those paying their own way. Yes, you can occasionally catch a deal and you may have miles to burn on upgrades, but if Global could offer the equivalent of biz space, even without the latest lie-flats along with even premium economy service at say a 50% premium over cattle class, the economics could work and most travelers would find it to be quite the deal.