Actually, it is a fairly even handed article although the title is a little sensational. I think most would say the 787 has had a rough development period with delays and issues. It is now at the ramp up stage with much of its risk retired for the 787-8. It is likely the 787-9 is on firm footing, but things can show up in flight testing for any aircraft.
Airbus has had its own issues with the 380 (a400m, 350, helicopter division, etc.) with which they are still trying to fix in a timely and efficient manner. They have an opportunity to launch the 350 smoothly, but likely there will be some issues. Since it is a more conservative plane than the 787, it could be argued that they will have less risk. On the other hand, they will have less advanced technology to take advantage (potentially). Of course, new doesn't always mean better...
If Boeing had been flawless in execution, they would have had a longer lead. They still have a lead, it depends on who stumbles and who executes. I still see issues in 5 years for Airbus in the 200-300 passenger capacity planes as the 330 will have a harder and harder time competing with the 787 IF
the 77 ramps up successfully and IF
the planes deliver the promised results and IF
nothing else show up as issues.
As for losing sales to the 350-1000? The margins are so tiny for airlines now that they will have to maximise every percent that they can in purchse and in operating costs. Fuel is taking up a much larger percentage of the operating cost so the more efficient jet for each segment is in general going to win. I would predict that there will be a lot of mixed buys from the airlines as they will be pairing the best fit aircraft to their network mix. The advantages of a single manufacturer fleet is going to be less as they go to power by the hour contracts and outsource maintenance to third parties or use general maintenance companies.