I think that's a tough answer:
The GTX950 will give you decent performance for 1080p gaming for....2 years or so. Not bad, since most gamers replace their GPU's every 2-3 years anyway.
Stepping up into R9-380X/GTX960 4GB is about 25% more performance than a GTX950. That might get you another year on the replacement cycle. The good thing is these cards come with 4GB VRAM which will be helpful for handling future games.
This EVGA 4GB GTX960 is currently on sale for $170 after MIR and includes Rise of the Tomb Raider game for free. (top of my want-to-play games list) For the same price as an R9-380 or 2GB GTX960, it's a no brainer if you were looking for something better than a GTX950.
I probably wouldn't recommend the 2GB GTX960 or 4GB R9-380.
TR's testing showed the 4GB R9-380 performing slightly lower than the 2GB GTX960. Which would make sense given the two cards
cost about the
same at $165-$170 after MIR. The kicker is, that performance tier is only about 15%** more than a GTX950, which can be had for
$120-$125 after MIR. Doing the math: $125 x (15%) = $143. So you're getting more performance for your $ with the GTX950.
** Based on
this TR article with the 2GB GTX960 and the GTX950.
16nm GPUs are less than a couple months from launch. This is a big deal since we've been stuck at the 28nm process node
for 4 years. AMD/Nvidia have made performance improvements at the 28nm node, but there isn't much substitution for a process node shrink when it comes to adding performance. It allows you to squeeze more resources onto the GPU die. At this point in time, most people are leaning toward the cost-effective GTX950 as a tide-over option until next-gen GPU prices stabilize. I'd predict the 16nm GPUs will be highly sought after, prompting many GPU upgrades among enthusiasts. Even if you're not on the 16nm bandwagon, AMD/Nvidia are starting to lower prices on their current gen cards to clear stock for the new ones. People looking in the higher performance tiers (R9-390/GTX970 and above) can/should wait to see how the next gen GPUs stack up. If they fall short of expectations (likely from overpricing) you can snag a 3xx/9xx card on the cheap.
Main: i5-3570K, ASRock Z77 Pro4-M, MSI RX480 8G, 500GB Crucial BX100, 2 TB Samsung EcoGreen F4, 16GB 1600MHz G.Skill @1.25V, EVGA 550-G2, Silverstone PS07B
HTPC: A8-5600K, MSI FM2-A75IA-E53, 4TB Seagate SSHD, 8GB 1866MHz G.Skill, Crosley D-25 Case Mod
.