Maybe the 500s or 600s are a marked improvemnt over the 300s. I fly LH
to Asia on the the A340-600 about every 6 weeks or so and this is the best longhaul experience I have had in the last three years. Comparisons being AA
767s betwen th US and Europe and BA
in 777s, again, over the north Atlantic. On company business, anything over 5 hours is Business Class for me, so if you have been in economy, my comments might not be particularly relevant to you.
Curiously, I did not enjoy the BA777 because the seat was too big
for me- in some positions my feet couldn't comfortably touch the ground!