I agree with others that the onboard product (both hard and soft, in my case) and price are the main factors in my buying, rather than the airframe. The only relatively recent exceptions to this have been the B787 which I was avoiding for a while, and the fact that I recently changed my summer trip outbound leg so I could fly on an A380 (marginal difference in timing and a choice of that or a 777-200).
That is not to say that I don’t have opinions about aircraft – the B777 is my least favourite long-haul plane, for instance, because I find the noise and vibration from the engines harsher than on any other modern airliner. I suspect the contrast with the A380 will be quite marked! I have a soft spot for the A340, which in its day had much better air quality than its competitors. The aircraft I am most looking forward to flying, however, is the A350.
What I still don’t understand is why Airbus have both the A330 and the A350 in their line-up (they are pretty similar size-wise), and no obvious competitor to the B777. Very odd.