Real owners lean toward the Sennheiser HD 650: 75% of 316 owners recommend it, vs 35% of 474 for the Bose QuietComfort Ultra Headphones (2nd Gen).
Verdicts aggregated from Reddit, enthusiast forums, and YouTube owner comments — affiliate reviews excluded. Sample sizes differ; judge accordingly. How we score
“My ultra used daily for over a year is still working great. Had some firmware issue at the start but currently it is Ok. Good anc, great sound and sturdy.”— GrumpyBitFlipper on Reddit
“I come from the xm5 earbuds and just bought the QC Ultra 2nd gen’s because even though I loved the Sony’s, I don’t like wearing them knowing there’s too much toxic chemicals in them.”— therealpurpledolpin on Reddit
“but not the Ultras (not worth the price increase imo)”— xolavenderwitch on Reddit
“What an incredible difference they make to everything I had before! You can listen to a track and hear subtle details that you did not even know they existed. Wow!”— @marco83 on YouTube
“HD650 with a bum driver, but I was able to solider the voice coil back on, so they work normally again. I had a pair 15 years ago and always regreted selling them.”— kindofbluetrains on Reddit
“I find the HiFiMan Sundara & the Fiio FT1 Pro both more useful for mixing - the Sennheisers have a much more condensed/flat sound with less bass extension than either of those”— @reallyoldcob on YouTube