Originally Posted by
NWSRG
Maybe this is a slightly naive suggestion...
...but would buying both not be the best option for the US Army? Common engines (I think?), potentially commonality in avionics, but different platforms for different missions. Not to mention, keeping the ability to manufacture military helicopters alive in two rather than one organisation (accepting that each involves multiple players). The SB1 looks like a much better replacement for the Apache than the V280, but on the other hand, the V280 looks very good as a Blackhawk replacement...
I think most serious engineers would tell you that no single configuration is best all all missions ranging from light scout to ultra-heavy lift. A mix of ABC, tilt rotors, and yes, even conventional helicopters is what will best meet the USG performance vs. cost goals for each mission need.