Noise cancelling headphones that works for me

After reading so many reviews of many noise cancelling headsets (sony, bose, seinheiser), I decided to go with te PXC-300. I don't have any comparative experience with noise cancelling headsets. After much research, I was looking for something that's not too huge, but also does the work. So I don't know in real if any other headphones are much better than seinheiser. Although the reviews were good.
One of the things many do not understand about noise cancelling is that the concept itself. Many think ,that NS headhphones cancel all noise outside. Noise cancelling does not cancel all outside noises (conversations, etc., ). They may reduce them. Certain noises (humming, a/c, jet engine, car engine and similar) which are continuous can be recognized by the circuit effectively, and it outputs a noise that cancels them out.
First when I brough it, I was at my home, and I turned on the window air conditioner (a bit noisy) and I noticed, as soon as I turned on the switch on the headphones, it cancelled about 80% of the noise.
Also I noticed that, sometimes when you cover your ears with headphones or with your hand and when you talk , you can hear yourself through your own vibrations in the ear. This also happens when you have regular headphones in your ear or if you cover your ears with your hand and try to eat something, you can hear your own vocal noise and vibrations. Amazingly I noticed that this noise cancelling headphones also cancels them completely.

One thing is that these headphones come with a dangle in the wiring (about 5 inches x 3/4 inches or so) which has the circut built into it. The reason is that they wanted the headphone itself to be compact and be able to gold into something small. So the dangle was a compromise on the size of the headphones.

Next, when the battery runs out( I don't know who in the seinheiser engineering division engineered this, but it was really stupid), suddenly you will get this annoying high volume low pitch (alarm kind of) noise , that will wake you up with shiver, if you're in sleep on a flight.
I was wondering why couldn't they just turn off the sound, when they realize the battery is running low or give a low volume beep or something. So stupid.

But atleast, if the battery runs out, you can still use the headphones without the noise cancelling functionality. I'm not sure if the Bose headsets allow that. So that is good.

The battery that came with it lasted for about 5 hours or so (Not sure if it was completely full). Takes 2 AAA batteries.