I used to believe the blurb that the V2500 is the quieter until I had first hand experience both as passenger and on the ground.
For a long time I had only flown (as a passenger) on A320/321 of bmi and BA. I couldn't believe the difference when I first flew in a CFM engined A321 of Aer Lingus. The fan buzz being significantly less during full power and climb. I've confirmed this with easyjets new A319s.
I'm quite prepared to accept that it's subjective, but then perception is what matters with noise, figures mean nothing.
The article of the supposed superiority of the V2500 is interesting. I recall reading recently that A321 with V2500 are only "marginally" compliant with Chapter 4. I take marginally to mean in this case that there may need to be operating restrictions to remain within the spec.
I live under the flightpath of BHD and the transition from full power to climb is very noticeable. The annoyng feature of the noise, the buzz, worsens. For my money if they are backing off to reduce noise impact they shouldn't bother.
I can pretty much tell the A320 from the A321 too. We had a quiet winter last year with only the A320 in service.