My QC25 bought new for 120$ are damn awesome. Half of my office tried them over last year and the conclusion was unanimous - they are great. Office noise is cut completely including most of the normal talking. Airplane noise is cut especially effectively, it seems they are optimized for it. Old subway and old trams are very high frequency and are cut only partially but still noticeably. As for build, soft materials look flimsy but neither band nor earpads are torn or degraded after 1 year of usage (office and rare travel), cord is good too. And wires in the moving part of headset looks very well implemented.

I think up to 200$ ANC headphones are a very good buy, 350$ is debatable.