There's plenty to complain about for customers of both Boeing and Airbus' latest tankers. The obvious difference between the two is that the Airbus product is currently operational with 4 nations and the KC-46A prototype is yet to fly.
There's a possibility that the delays Boeing are experiencing might mean a more mature product at delivery, without some of the teething problems that the A330 MRTT has experienced. But then again, when was there ever a new aircraft type that had no teething problems?
You can argue that the 'Scrapheap Challenge' comes to mind when you look at the KC-46A design, or that the A330 MRTT build process is akin to taking your shiny new Ford Capri to 'Pedro's Body Kit, Paint and Detailing Shop'. Both options may have their flaws, but both designs must meet rigorous design and safety standards, comply with contract specifications and be accepted by the customers.
The greater concern for the USAF must be how to generate enough tankers every day, amending any drawdown plans and extending airframe lives to maintain capability during any known or forecast delays to delivery. Considering how many nations other than the US rely on AMC tankers and the NATO requirements for AAR, any delay to the KC-46 may have effects that reach beyond Washington State.
I wonder if Ulick is dusting off his boom designs and having those ex-JAL DC-10s serviced?