Shure SRH440 vs Bose QuietComfort 25

Sound signature is fairly neutral, with slight elevations to the bass, mids and highs.
Bass has a nice fullness to it, with some extra depth which gives the sound a lot of body.
The mids are neutral but slightly forward, making the vocals sound really clear. Aggressive guitars can sound a bit harsh because of this though.
Treble has good extension, and the added peak on the highest frequencies add more sparkle to the sound.
Overall, these headphones can be used both for critical listening and for casual music enjoyment as well.

The closed back, over the ear design blocks out a significant amount of noise, allowing users to easily focus on the audio. Sound leak is also kept to a minimum.
These are great for tracking and monitoring, and are also great choices for use in quiet environments like a library.

You can easily remove the cable when these are not in use, making them easy to store. This also makes the cable easy to replace when needed.

The traveling case is small and provides room for spare batteries and other components. This makes it pretty portable, for those that can't or don't want to leave their headphones at work.

These headphones use a triple-A battery to power noise canceling. Should it run out of charge, it can easily be replaced.

With the feature switched on, you can really zone in on the music. Noise canceling is very effective at blocking out ambient noise, especially the lower frequencies. On a flight for example, engine noise is drastically reduced, as well as most of the sound from the conversations in your vicinity.

The QC25 feels comfortable even after wearing it for several hours. The pads go over the ear and feel soft, as the ample cushioning is covered with supple and high quality synthetic leather. Aside from the usual headband padding, it also has an inner Alcantara lining that feels really nice on the skin.

You have a number of options as to how you want to use these headphones' active noise canceling feature. You can either have the feature on or off while you are listening to music, or have noise canceling on without audio. This is a nifty feature if you just want to enjoy some peace and quiet when in a noisy place.

These headphones will not tire your head or neck out, even if you wear them for quite some time. These are pretty light at around 196 grams.

Sub-bass is a bit laid back, but the overall low-end production is punchy and with good extension. Mids are clear and forward so vocals, guitars and keys sound good with these. The upper treble is boosted, which results in good detail, but can also give harshness to the sound.
Overall, this is a really fun set of cans to listen to, especially if you just want to have a fun music listening experience.