Pani,
When discussing cartridges it's critical to know which tonearm will be used. No one can give reliable information about a cartridge without knowing that. It wouldn't hurt to mention the phono stage either.
Take those statements about how ZYX's don't rock with a grain of salt. Anyone who makes such simplistic claims without providing their system context lacks a certain breadth of experience. How well a Yatra or most other ZYX's rock depends to a great extent on the tonearm, particularly its effective mass. On an arm with an effective mass of 18g or a little above, a Yatra will rock the house while also providing natural detail and tonality. On lighter arms the singing detail will still be there but you will indeed get less rockin'. My guess is that those who claim ZYX's don't rock have only used tonearms of 15g effective mass or below, perhaps much below. The devil is in the details.
The best ZYX for rock/pop is the 4D, which rocks as well as any cartridge I've heard, even on an 11g TriPlanar. That's a different design from the R100 series and well beyond your price point, but it heartily disproves any foolish notion that "ZYX's don't rock". Read our review of the 4D (Atmos) beneath my signature for a discussion of why/how some ZYX's rock better than others.
I defer to Syntax on the Delos, which I'm unfamiliar with. He seems to know what he's talking about there, as usual.