Yeah... you'll probably like the sound of the "new version" Senns better than the Stax / Koss sound... if... you prefer a rich, bold sound to a somewhat cool, refined sound.
After trying the Stax... I found I prefer the sound of the "new version" HD580/600/650's, the AD2000's, and the RS-1's to the Stax... though... the SR-507's are close (the O2's just require far too costly amps to rival these dynamics).
And... there really is no contest... when you consider the relatively low cost of a Senn setup.