Overall, all 3 headphones come at very similar price points and have similar target audiences. Now, let's recap and break down the differences to further understand which is the best for your ears. First, the Sennheiser HD 450BT is the cheapest out of the bunch. It has the best sound quality and sound customisation, as well as great noise-cancelling that rivals the Razer Opus. Next, the Razer Opus is the newest headphone with its subtle design and best noise-cancelling, it is arguably the more stylish headphone compared to the Sennheiser HD450BT or the Sony WH-XB900N. It may not have done so well with songs with heavy bass but it makes up for that in its bright, clear and articulate vocal and instrument works. Next, we have the bass-heads favourite, the WH-XB900N with its subtle branding and minimalistic design. It may look plain outside but I guarantee it packs a serious punch when the bass drops. In terms of overall ranking, the Razer Opus ranks first; excelling in the design and build quality, noise-cancelling and portability. However, the Razer Opus sound quality is something you definitely want to consider if you don’t like headphones with a lack of bass. Those looking for the best overall sound quality and noise-cancelling, should go for the Sennheiser HD 450BT while those looking for the best bass-focused noise-cancelling headphones should go for the WH-XB900N.