Well, if you take a look at the
GPU hierarchy chart, and scroll down to the Legacy Chart section, you'll see that the 780 is roughly on par with:
- Nvidia:
- GTX 780Ti
- GTX 970
- GTX 1060
- AMD:
- HD 7990
- R9 290
- R9 290X
- R9 390
- R9 390X
- RX 470
- RX 480
- RX 570
- RX 580.
Comparing to cards still available new, with warranty, currently in the US you can pick up a Sapphire Pulse 4GB RX 570 for $119.99.
The 780 is a used card, with less memory, and a pretty obnoxious 250W TDP. I don't think I'd personally look at it unless it was half the price of the RX 570, or less. Maybe that makes me a cheap SOB.