i posted a mini review in the headphone section, i own the studios and a pair of senn hd 598, the senns blow the monsters away when it comes to realism, but they are abit light on the bass. the monsters whip ass when it comes to bass and they definately provide alot of detail, but i do think they emphasis the mid bass a fair bit,but i bought them for when im traveling, and for this purpose they are spectacular. the noise cancelling works really well, and they cut out alot of the backround noise.
the monsters are also better built than the senns and come with a nice travel bag, and special cloth, and airline adapter and 2 cables. for critical listening at home, i choose the senns, but because they need a proper amp they not good for traveling. the monsters have a built in amp (for the noise cancelling) and if you plug em into a ipod or laptop they really perform well with no long term listening fatigue to speak of, and shine when it comes to rock, electro and so on, anything with a driving beat, think linkin park or nine inch nails, make the monsters sound awesome.