Sennheiser HD 650 vs Bose QuietComfort 35

The sound signature is near neutral but with a little emphasis on the lower frequencies. The bass is slightly forward with good punch and tightness. Explosions will have good rumble, without overpowering the other frequencies.
The mids are warm and clear, adding extra body to the sound. Game dialogue will be easy to hear.
Highs have good clarity, but are not forward in any way, so harshness is minimized.

The H650 is popular for its near neutral sound, which makes it quite versatile. The headphones can give a great casual listening, gaming, and movie watching experience yet are accurate enough for pro audio mixing. They are also lightweight and comfortable so you won't have any issues wearing them for hours.

Clamping force is not too tight. The ear pads and headband feature memory foam which are covered by velour material. The pads feel really soft on the head and allow airflow for minimized heat build-up/sweat.
The headband also features similar cushioning materials and minimizes pressure spots on the head.

The open ear cup design allows the sound to blend with your surroundings, giving it a natural width. It will also be easier to identify the direction of sounds, which can really help immersion.

The HD-650s do not feel heavy at all. They are usable for long music listening, movie or gaming sessions without feeling pain or strain on their head and neck.

While the cable connectors are proprietary, they can easily be removed from the ear cups with a firm pull. The popularity of these headphones means that there are a lot of aftermarket cables that can be bought.

Bose's noise cancelling tech is quite effective at blocking ambient noise. This will help you fully enjoy the music with little to virtually no outside noise interfering.

With these, you won't have to deal with long and dangling cables that can be difficult to manage.

The QC35s can play music continuously for up to 20 hours. This should cover most of your trips' duration before needing to recharge.

Bose QC35 connects to 2 devices (for media and phone calls) allowing one to listen to music on the laptop and get calls from the cell phone. Allows to change the music provider (laptop or cell phone) automatically. With Sony or Senheiser all you can do is connect media on one device and phone on the other device... functional but really restricted one you get used with QC35.

The QC 35's ear cups and headband feature quality memory foam material which are soft and supportive so they do not pinch on your ears or apply too much pressure to the top of the head. These contact points are also covered with a quality leather material which feels nice and smooth on the skin.

Despite having internal batteries, these headphones are still fairly lightweight, coming in at 235 grams. This makes the QC35 really easy to wear for extended periods and even while traveling.

You can easily control playlist functions using the buttons on the right ear cup. These functions include volume control as well as the play, pause, next track and previous track commands. The on/off switch for the headphones is also on this ear cup.

Aside from Bluetooth connection, you can also connect the QuietComfort 35 to a source using a 3.5mm cable. This makes the headphones usable even with the battery depleted.

Bass is full and punchy. While the sub-bass is not pronounced, there is good and fast bass extension, and this is what gives the music punch and a sense of tightness.
The mids are full and slightly forward so vocals and guitars can be clearly heard.
The highs are clear and do not distort at high volumes. There is a peak on the upper treble which helps to add more detail and clarity to the music, but some may also find the high frequencies to be quite harsh at times.

Multiple microphones are strategically located on both ear cups, allowing for great voice quality when taking calls. The noise cancelling also helps to clean up the voice quality that goes into the headphones.