Just speculation here, but last I looked into it, video cards were worthless when it comes to ROI compared to the specialized mining hardware used nowadays, which is continuing to advance.
This wasn't true for Ethereum, at least last year when I was mining it with (used) R9 280xs. Depends more on the cost of electricity in your country.
EDIT: also, AMD graphics cards had a significantly better ROI than Nvidia cards.
However, an OCL-HashCat benchmark is something I'm definitely looking forward to.
Ethereum is ASIC-resistant, so GPUs are as good as it gets, at least at the moment.