I currently own three of Cowin's noise canceling headphones; the E7, E7MAX and E8. In my opinion the E8 is great if noise reduction is your primary concern and music secondary. I find both the E7 & E7 Max to be the reverse, music primary while noise cancellation secondary. I personally use these headsets for music/blutooth streaming.
Musically, the E7's sound is dynamic with deep bass that's not too boomy. The clarity is great. At this price point it is a great deal when compared other brands. The E7 Max is not as dynamic nor is the low end as deep when compared to the E7. However the E7Max's high end (treble) is "brighter" than the E7. At times a little too bright for my listening taste. Also the vocals on the E7 Max are slightly more distinct, making the max great for spoken word audio, vocal heavy tracks and phone conversations.
As of now, my preference is the E7 for music, I do use the other sets as well just not as much as the E7.
If Cowin's other product's are of the same quality as these it will be hard to find better value at this price point from name brand competitors.