effxz welcome to the forum. The headphones you mention are Monster Inspirations which are extra bass headphones and the Bose QC15 are for noise cancelling outdoor type heaphones. Neither of them is particularly well balanced and many characteristics of quality headphones like precision, soundstage, imaging will be lacking with these sorts of headphones. For the same price you could get Sennheisers HD598 or for less the HD558. These headphones are well regarded. More pure and expensive are the HD600s or HD650s if you prefer some bass emphasis. These headphones require a quality source and amplification which starts to get expensive. Beyerdynamics DT880s are good for cold neutral headphones or DT990 if you want a more V shaped frequency response. For $250-300 you should be able to get a fine set of headphones.