Whenever new planes get developed there are always growing pains... the battery issue was bad enough to ground the fleet of them - but that's also a good example of how they've worked to ensure that the issues aren't so critical as to be fatal.
I'm pretty sure they'll work out their problems - just as Airbus had to.
The same could be said of , say, a complex new healthcare system, don't you think?
I flew on the Dreamliner last week and can't say I was blown away by the experience. That could be down to the BA cabin layout, but I doubt the other major airlines will deviate far from the same configuration. The entertainment system was excellent, with a vast choice of films and TV shows (including 'boxed sets'. The 'larger windows' on the plane aren't all that large.
I felt pretty unfatigued after an almost 8hr flight, so the much vaunted cabin air replacement system seems to be doing its job well. The seats were reasonably comfortable, however, elbow room while dining is very restricted, more so than on any other flight I can recall (except on RAF transport ac). The seat in front had an annoying metal box intruding into the foot well, which prevents one stetching the left leg comfortably (all the seats seemed to have the same box). All in all, not a bad flying experience, but nothing special.