Performance
Going in alphabetical order, we’ll do Bose first, and Sennheiser next. The Bose proved to be a nice-sounding pair, especially with the NC circuit on. They are not too effective because their design leaks sound in acoustically, but does the job satisfactorily.
Sennheiser, on the other hand, sounds insanely good when the NC is off, just like regular headphones. In fact the acoustical noise canceling is very nice. When on, they just sound weird; the ears need some time to get used to the sucked-out pressure feeling. But they are effective if you look at it theoretically. And yes, there is a little noise in the circuit that’s induced and audible, when music is off.
Price and Logic
At Rs 19,900 Sennheiser just beats Bose, which costs just a little bit more at Rs 20,600. Some pointers favor Bose, but Sennheiser also has a case. Both are expensive (20K for a pair of headphones is a ridiculous premium), but for pure audio listening Sennheiser takes the cake. Still, we must add that Bose's noise cancellation is better!
Guys let me introduce you to another world of audio pleasure. Rise above Bose vs Sennheiser debate and try a Grado. Not the best looking haedphones but sound quality is above the two here. I have tried all of these and bought a Grado. Max bang for the buck 
