After 10 years on A330-300s and moving over to the A320/321,the noise level difference is very noticeable. The ground noise due to the blowers and the general noise level in flight on the 320 can make one a little cranky after a long day, 4+ leg tour
.The 321 is better in flight when you get it there.
I have been using a Airman 850 for the last 3 months and can only recommend this headset. No batteries,lightweight, comfortable and around 10db less for the nerves. It comes with the correct 5 pin plug and the correct impedance
for the AB / Boeing intercom system, no extra cables or hot mic's and very clear, low volume ATC.
Generally though, not enough is done by the design of cockpits in respect to noise, temp control, lighting, seating and placement of certain instruments (FMCU etc).Maybe the new generation 787/350 etc have had a little more pilot input