And why do they never release the actual numbers? The last actually released mechanical property figures slipped drastically below the strength of steels above 2*mm* in length. Making them in visible quantities hasn't been a problem for years, the issue lies not with their 'difficult to work with' nature, but their utter sensitivity to thermal vacancy defects, defects that they *cannot* be made without and increase statisticallty with the temperature of manufacture. It is these defects that limit strength and the bigger you make them, the higher the probability of defetcs existing in the structure, a structure that requires perfection to achieve these magnificent strengths.
I'm not saying that the theoretical strength of these materials isn't incredible, but the thing about materials science is not what you hope it will achieve, but what thermodynamics lets you achieve.
I notice that no-one talks very much abotu the explosive strain energy contained in the structure, either. The propogation rate of energy release in these things at failure is about 50% higher than an equivalent mass of *TNT* :-D