depends on what you're after in terms of sound quality.
the akg q701 is more high/mid focused with poor bass output and tend to be rather bright on treble, almost sibilant. the sennheiser hd598 is fairly neutral across the board with a tad more bass and is more smooth sounding instead of detailed which makes it a bit less fatiguing.
the q701 is more comparable to the ad500x/ad700x than it is the hd598.
for movies and music not just gaming i would say the hd598 is better suited. if you're looking for brighter headphones or something with more bass kick yet still open design then perhaps the dt990/dt880 are worth reading about as well.