Pros: Comfort, large soundstage, clear audio, design
Cons: Pricing, bright trebles, large redundant box
Let me start off by say that i am not a perfectionist nor am i a totally audiophile, but rather an enthusiast (because my rig is mostly mid-fi) that never really found any need to post a headphone review, but since the HD700 has been getting mixed impressions i'd like to give my opinion, also i've only listened to the HD800 for around 30minutes therefore i will not compare them (c'mon guys its Sennheiser's flagship headphone for a reason).
With that out of the way i can now get to the actual headphone, which i believe has i very unique design which to me looks like a face-lifted version of the hd800 albeit made with slight less premium materials. It also comes in this extremely large useless box and no accessories.
For the first 10 minutes of listening i found the soundstage to be incredibly wide and the low end surprisingly punchy (guessing its them trying to get some of the HD650 sound signature), the mids were there and was very flat, what i was most impressed was the fact that it would always keep up with the music even when there was a lot of instruments going off in the background it would still bring out every detail, the HD700 is very comfortable though made from plastics (at least it seems durable).
After 4 days of burning in and listening, i believe that the hot treble has smoothened (though i also highly predict that my ears have simply gotten used to the sound signature) and it retained its super detailed and clean approach towards projecting my music.
In comparison towards the HD650:
Though i never owned one, I've listened to a HD650 for around 3 hours recently and always found to be very warm, detailed and punchy. This i believe, is a stark contrast towards the HD700 because the HD700 has a more clinical sound albeit with a slightly punchy low end and hot treble therefore leaning towards the HD800.
In comparison towards my other headphones:
HD700 blows the others out of the water.
In conclusion, i am really impressed with the clinical yet slight "fun" sound approach taken from the HD650 which was exactly was i was expecting when purchasing these headphones therefore i have no problem paying full price, i understand why some cannot justify its asking price because i believe its not a direct upgrade from a HD650 but rather a sidestep with newer technologies implemented inside the headphone.