Busta, Notice I included the GXSR750 in my argument as an example of Suzuki's Aeros, The W Series GSXR750, like the ZX9, is faster than it *should* be, the GSXRs excellent aerodynamics, peaky engine with loads of overrev and slightly tall gearing make it a giant killer in certain circumstances, just like the ZX9 for exactly the same reasons.
I suspect the Busa and ZX12 will both be within a couple of MPH of each other, and I suspect it's the Busa that will deliver it's top speed under most conditions where the peakier more aerodynamically sensitive (hence the winglets) ZX12 will be faster in perfect conditions but will come second on blustery days or with two way figures.
So the mags will try and try eventually getting the best out the 12 and then crown it king when it was the Busa that delivered the goods everytime.
I don't think there will be a definitive answer to what's faster until Suzuki tweak the Busa, it's softly tuned engine has tonnes spare, another 10-15BHP would be a piece of cake and could be gained just upping the CR a tad (which is quite low) before they even bother looking at tweaking the mild cam timing or fixing the leaky ram air, after breathing on the engine take a tooth or two off the back sprocket and wave goodbye ZX12 which is already much nearer to it's potential limit (as a stock bike.) than the Hayabusa, which (like the ZZR1100 before it) is good enough to stay ahead with little tweaks for years - Suzuki were no idiots when they made the Busa a 1300!