Great sound quality
Bose qc2 headphones are great for you if you one of those who care much about sound quality, especially the bass. The headphones are just delivering good quality sound that makes the mp3 being played like a live band performance especially for you. Together with the great sound isolation function, the sound quality is simply upgraded to another level as you would not be disturbed even when you are on a plane!
One AAA battery for 30 hours
You would need an AAA battery for the headphones to reduce the sound around you. So you have to keep some battery stock with you. But considering just one AAA battery can let it run for 30 hours or so, I would say it is economical. And plus the fact that it surely would not be difficult for you to buy AAA batteries regardless of your location so the battery idea is good. Also, it is not like you have to bring a charger with you all the time so as to let the Bose qc2 headphones work so it is a convenient energy form for many too.
Bad for traveling
To enable a design so effective in blocking the sound in the background all out, the cushions of the headphones are far from the word "thin". Therefore, the headphones have been made to be relatively think comparing to other sound isolating headphones you can find on the market. If you are a frequent traveler and would like to buy a pair of headphones to go with you all the time, you may not want to purchase a pair of Bose qc2 headphones as the size of them does take up quite a large space in your luggage as I suppose making your luggage as light as possible would be very important to you.
Not for long wear
Though the sound reducing function of the headphones is very great, you may not want to wear them for a very long time as when the isolation is so good, you may not feel very comfortable for having the headphones on your head for a long time thinking about the size and the weight of the headphones. In addition, the cushions around your ears are almost sure to make you sweat, especially if you are living in somewhere hot. Thus, it would be best to just use your Bose qc2 headphones for an hour or so. Anyway, they may help to keep you warm if it is winter time!
Not cheap anyway
You can imagine with the kind of quality of sound and the sound isolation function they offer, Bose qc2 headphones is not going to cost you just a penny. The price of the headphones honestly is not low. The price tag of them may be having the figure double or even triple to the one you have paid for your current audiophile so you may just have to think about it that if you do require what the Bose is offering.