Well, perhaps that's simplifying it a bit in retrospect..
For me it's more what the Zeus is more suited for compared to my other options.
Almost anything Vocal really brings the best out in the Zeus, sure it can be used for rock/pop but it's where the VE8 is better hence to me the zeus was made for other genres.
I can also go for the "best" recording with the best sound.. But sometime i just want to listen to good songs and stamp my feet no matter how it was recorded and what year, and that is where i feel that to mee the VE8 has the upper hand.
However when i really want to enjoy listening i usually so far use my Zeus and put on some Zelmani, Torrini, Obel, band of horses, and those kind of artists which i enjoy both musically and also how they sound with the Zeus.
Actually also my all time favorites Depeche Mode also sounds quite good with the Zeus. Or why not Alphavilles: forever young record(can't believe it's 35 years old, still going strong and in some strange way sounding fresh..). (Also good with the VE8 )
But, a bit of increase in bass and a slight drop at 8khz makes the ZEUS more versatile to me, e..g can almost touch the VE8 when rocking it. or similar
well, Muse, Live, Bush, Oasis, White lies and the likes..
You can see that i'm probably way more "mainstream" then some others here, but i still want it to sound great.