We have two unrelated animals here for 787 read A350 for A380 read 747-400 or series 8 see the 787 more of a re-placement for the series 777 which is 80s belt and braces technology. Airlines are currently ordering 777's as stop gap capacity for the next large civil transport, who's? Airbus or Boeing!!!! read on.....
The 747-8 despite Boeing protestations is very much still 70s technology with some embroidery and in the case of the 8 series two fuselage plugs, hardy ground breaking technology, with the exception of Lufthansa it's universal rejection by the all major carriers is spectacular.
For cabin quality noise & environment the 380 & 787 though not fighting for the same market are mammoth steps forward in technology terms, the next step will be demonstrated if we believe Airbus by the A350 and the learning curve they will get from Boeing's 787 introduction.
Ultimately the way air travel volume and slot availability is moving meand Boeing will respond to the A380 Airlines are asking them to do so & we will see the 747-400- & series 8 re-placed. Profitabiity of the 787 until the A350 arrives will enable Boeing to finance the development project.
Whilst the technology does not yet exist to make safe composite tubes to the A380 diameter or length construction/design will be similar to the approach taken by Airbus with the A350
It's difficult to see how Boeing can improve significantly on the A380 in it's own design so at this point the per mile cost and environmental advantages are seen as minimal or now existant, it's more about dropping the 777 in eight years approx and meeting airlines demands to Boeing for a large transport as an alternative to Airbus's A380
Which to choose, the larger cabin of the A380 makes for a more quiet, pleasant and stable flight, humidity levels claims for 787 personally I have never really thought about or suffered humidity problems on long haul, I'll go on plane on any route, the preffered choice as with A320 over 737 & 340 over 777 would be the A380 thanks....