GTX 660 vs mis Radeon R9 280 TWIN FROZR

I am currently building a PC using the Radeon, however I will soon be acquiring the Nvidia Shield Tablet and I have been told that to stream PC games you have to have a video card from Nvidia from 600 series or above. Is that true? If so is it worth the move? All help is much appreciated!

Need gtx 670 or better. Need Kepler gpu for that.

 

My suggestion is the gtx 760. Pick on up for $230. 

@ Ritual_Watermelon Well, I think that it would be best to get a Gtx 760 Or 770 it really isn't worth it to Get a 660 because even the 270 beats it

He wants shield for his tablet. Has to be 670 or better.