Sony MDR-1R MK2 and B&W P7 a few weeks later
Comfort
No contest. As above, the Sony's feel like a cloud is hugging your head. Frankly if you cannot get on with the fit here then you might as well forget this category headphone entirely. Supreme comfort.
The P7 will be more personal. Clamping force is greater and the border of the pads will press on your head. Thankfully the pads are larger than on-ears and will not touch your ears. Benefit to be had from wearing in. If you are feeling the squeeze try using books overnight. Or 'persuading' the band gently and stretch out.
Build and Isolation
P7 is bigger profile and bigger build than the Sony. Sony looks nice but no hiding all-plastic feel. Despite the extra clamping of P7, isolation seems about the same between them. Where they differ is that the Sony suffers from wind noise and there is a touch of plastic creaking. Limited recommendation for Sony. Walk to local park or shop on a nice day it is fine.
Sound
Both will play nice with smartphones, Sony is hair more efficient. Actually more similarities then differences. Most people will like the bass extension and treble. Mids and vocals sound as they should. No trace of sibilance to these ears. Detail retrieval is about equal. You can pick out decay on guitar string plucks. Both engaging and forgiving.
Where they do differ is that:
(1) P7 wider and greater separation between each element. The Sony is closer sounding
(2) P7 treble is more prominent in the mix, particularly noticeable with cymbals. Not grating treble like budget Grado mind, but will be matter of taste, experience, perception and your source pairing.
(3) Conversely V-Shape of P7 when a/b-ing becomes more obvious. On
some tracks you may turn up the volume to bring out the vocals. With that said if you have a decent DAC this is less of an issue and found P7 will scale, for example P7 responds well to clas -dB stack