I have bought both the 20i in Ears from Bose and the QC 25. The 20i in ears Noise Cancelation eats the QC25 NC for breakfast. Seriously, they are in another ball park. The 20i NC works like on pro-levels and let the NC in the QC25 seem like a Kindergarten toy across the whole frequency spectrum, the 20i cancelled noise better, a lot better, let it be water, clicking, birds, wind, voices, knocks, doors slamming. Whatever I threw at both of them, the QC25 did let through about 50% of the sound and the 20i about 25% of exterior sound, yes it is that good. So - if you are serious about NC better give the 20i in ears a try.
That being said, the sound on the QC25 is substantially nicer, the bass extends more, the soundstage is bigger and there is a lot more detail. I would even say I enjoy its relaxed, muffled down sound signature. But when in doubt I would never hesitate to opt for my Beyerdynamics which sound-wise is just no comparison to Bose products, which is unfair I know, Bose being cool overpriced and well-made gadgets and Beyer T51p being a serious headphone for adults. Fyi All A/B tests were done against an Audio Engine D1 DAC.
Then there is the ground level white noise, which is much louder with the 20i, almost making me hate them. Also the "pressure" we know from NC is much more on the QC25, but its bearable. Before I make a decision which one to keep I will take them to work. Because of much less leakage and superiour NC I will probably opt for the 20i or as an complete alternative for some cIEMs made out of silicon.
Thing is,I wear specs so the on ear design of qc3 will be great and it's rechargeable too.
