jmanusa6 :
I would go with a used 270x off ebay. Its much cheaper, the 270x performs better, and supports more of dx12 features. Also computers don't use as much power as ya think so shut up about tdp and power consumption on gaming pc's.
You don't know what you are talking about. The GTX 950 is slightly better then the r9 270x. Go look at benchmarks. The power thingy, clearly you don't know a shit about PSUs. If the video card is requesting a number of Watts , the video card needs to get that number of Watts. Ur PSU need to be good enough to handle it. If not, the GPU may not work properly and you may risk damaging your GPU and other components such as CPU too. I would never ever go for a used GPU(especially for the long run)You don't know what that guy did with the gpu. He may have super-overclocked it or something. Something may be wrong with the card he is selling. Another minus of buying a used one is the warranty. You don't get any. I got 3 years at mine.
As a final choice, I got the Asus NVIDIA GTX 950 Strix because of the slightly better performance, energy-efficient(another thing to consider, you can save up money for the long run), new arhitecture: Maxwell, because it was much cheaper and because I wanted to try something new. (Such as Physx and that)(Had an AMD integrated video card. Still have it but not in use: Radeon HD 8570d)
Thank you for your interest and your post doe.