I am pretty sure there is a typo in this one, since the GTX-280 is a very old card.
So I am going to guess that you are asking about 780/680 vs 290x.
That out of the way, there isn't anything out right now that can compete with the R9-290x, *but* it is a very loud, very hot card.
I would strongly suggesting going with an aftermarket cooling solution (Gigabyte / MSI / Asus) as they are more efficient, and quieter. Or watercooling it if you can.
So price / performance definitely the 290x.
If you are worried about powerdraw or sound get the nVidia.