Build Quality: The build quality is exceptional. I have owned my pair of Bose Soundtrue in-ear headphones for about a year, and they have been pulled on, sat on, and generally abused, but they don't seem to be at all worse for wear. The QC20s have a similar design, except that they have much thicker cords, so I am not at all worried about the longevity of this pair of headphones.
Comfort: The comfort is good, but not perfect. They do not sit quite as comfortably in my ears as the soundtrues (which are by far the most comfortable in-ears I have used). They penetrate somewhat further and are somewhat tighter feeling, though they are still plenty comfortable for a long flight if I don't jam them in too far. You may get better results than me, either with the default or the smaller or larger inserts provided. They are also a bit less comfortable than the QC15s and 25s. However, I tend to sleep leaning my head either to the side or leaning forward with my head on the tray table, and these allow a greater range of movements and head positions than the QC15.
Noise Cancellation: Almost universally acknowledged to be the best there is, so there isn't much to say in this regard. They are certainly in the same league as the QC15 - perhaps even better, and from what I've heard, same with the QC25 as well. How good are they? Traffic becomes mostly inaudible. An airplane cabin becomes a room with an air conditioner.
Sound:
Soundstage: A pretty limited soundstage, but this is to be expected in a closed noise-cancelling headphone. They may be marginally better than the soundtrue, but are worse than the QC15 in this regard.
Bass: Good bass response, deeper and bigger, though perhaps somewhat less smooth sounding than the Soundtrue or QC15.
Mids: The weak point of the QC20s in my opinion. The mids here are thin and I wish it could perform as well as either the Soundtrue, which is good, or the QC15, which is pleasantly warm and detailed, in this regard. Not a dealbreaker though once the brain burn-in kicks in. I find the QC15 somewhat fatiguing in the way that Bose headphones typically are, where the pleasant warmth means a loss of fine detail and added muddiness. Perhaps the new QC25 is better in this regard. Thankfully, the QC20s don't have this at all. The upper mids are emphasized to the degree that they can sound strident.
Treble: The treble response is strong, but not overly emphasized. In fact, it may seem recessed to those used to bright sounding headphones.
Detail: I find them to be at least as detailed as the QC15s, and slightly better than the Soundtrue.
Overall sound: The QC20 is a somewhat bright, dry and analytical sounding headphone. It is a bit strident compared to the Soundtrue or QC15 at similar volume levels. If you prefer the typical warm, pleasant Bose sound, go for the QC15 instead. The QC15 does a better job in a lot of music, particularly pop and rock due to its warm, smooth mids. However, the QC20 did better than the QC15 when I listened to Beethoven's symphonies and Rachmaninoff's piano concertos, and Nick Drake's sparse vocals and guitar.
Conclusion: The QC20 is the in-ear headphone with the best noise cancellation, and the sound can be very good if you don't expect the world, or if you prefer music that favors a brighter than neutral, dry sounding headphone. If you prefer in-ear headphones due to their flexibility, get these over the QC15 or 25. However, if you prefer comfort over flexibility, you may prefer the over-ear headphones.
Comfort: The comfort is good, but not perfect. They do not sit quite as comfortably in my ears as the soundtrues (which are by far the most comfortable in-ears I have used). They penetrate somewhat further and are somewhat tighter feeling, though they are still plenty comfortable for a long flight if I don't jam them in too far. You may get better results than me, either with the default or the smaller or larger inserts provided. They are also a bit less comfortable than the QC15s and 25s. However, I tend to sleep leaning my head either to the side or leaning forward with my head on the tray table, and these allow a greater range of movements and head positions than the QC15.
Noise Cancellation: Almost universally acknowledged to be the best there is, so there isn't much to say in this regard. They are certainly in the same league as the QC15 - perhaps even better, and from what I've heard, same with the QC25 as well. How good are they? Traffic becomes mostly inaudible. An airplane cabin becomes a room with an air conditioner.
Sound:
Soundstage: A pretty limited soundstage, but this is to be expected in a closed noise-cancelling headphone. They may be marginally better than the soundtrue, but are worse than the QC15 in this regard.
Bass: Good bass response, deeper and bigger, though perhaps somewhat less smooth sounding than the Soundtrue or QC15.
Mids: The weak point of the QC20s in my opinion. The mids here are thin and I wish it could perform as well as either the Soundtrue, which is good, or the QC15, which is pleasantly warm and detailed, in this regard. Not a dealbreaker though once the brain burn-in kicks in. I find the QC15 somewhat fatiguing in the way that Bose headphones typically are, where the pleasant warmth means a loss of fine detail and added muddiness. Perhaps the new QC25 is better in this regard. Thankfully, the QC20s don't have this at all. The upper mids are emphasized to the degree that they can sound strident.
Treble: The treble response is strong, but not overly emphasized. In fact, it may seem recessed to those used to bright sounding headphones.
Detail: I find them to be at least as detailed as the QC15s, and slightly better than the Soundtrue.
Overall sound: The QC20 is a somewhat bright, dry and analytical sounding headphone. It is a bit strident compared to the Soundtrue or QC15 at similar volume levels. If you prefer the typical warm, pleasant Bose sound, go for the QC15 instead. The QC15 does a better job in a lot of music, particularly pop and rock due to its warm, smooth mids. However, the QC20 did better than the QC15 when I listened to Beethoven's symphonies and Rachmaninoff's piano concertos, and Nick Drake's sparse vocals and guitar.
Conclusion: The QC20 is the in-ear headphone with the best noise cancellation, and the sound can be very good if you don't expect the world, or if you prefer music that favors a brighter than neutral, dry sounding headphone. If you prefer in-ear headphones due to their flexibility, get these over the QC15 or 25. However, if you prefer comfort over flexibility, you may prefer the over-ear headphones.
