Hi OP. Few things.
-Power difference will only be while gaming with an AMD ZeroCore part. I like the R9 380. It's latest gen GCN 1.2.
-The VPU market is a very mature market, most people are fooled by benchmarking sites using ultra settings and high AA/AF levels, some even 4K, which I don't know a soul with a 4K monitor!
-$200 or less is the sweet spot because nothing can really do 4K well enough yet or VR in a single card. I expect the AMD Fury X2 dual Fiji to be the 1st card capable of both and do it right.
-I disagree with the forum majority that the 960 is a terrible card. It was terrible on launch for the price, and the 128bit mem interface sucks. But it's not "terrible". It's NV's best offering at that sensible $200 sweet spot.
-The $200 and under range is where most people should be buying, that's the 1080 and down range. You can get away with even less if you're like most of us and play the games in the Steam top 10 list, Minecraft and League of Legends. I play at 1080P, no AA/AF, default settings in competitive games like Counterstrike Go and LoL using a R9 380.
It's very overpowered for my needs.. I'll get to why I chose it in a minute..
-Performance wise, the 960 and 380 are mostly equal.
-R9 380 > GF960?
Because a single 380 will do everything most people need to and more today and tomorrow. And once VR hits in 6 to 12 months, you may want that. You can buy another 380 and put them in Crossfire. AMD has the best VR setup in the market with LiquidVR. It achieves 100% scaling and can use 1 VPU per eye. It has fine-grained resource preemption which no Nvidia part has.
If you're even remotely thinking about VR, you want an AMD GCN part- preferably GCN 1.2 like the R9 380.. but they're all be better for Maxwell for this. Ask around to developers, it's true.
-The R9 380 is a 1440P capable card. Most VR headsets are supposed to be 1440P per eye. You won't be able to find a better priced VR-capable VPU setup than dual R9 380s.
-SLI 960s will not match the Crossfired 380s if you decide you want a VR headset in <1 year's time.
- Longer legs with the AMD GCN parts. They get faster over time and don't peter out like NV cards tend to do.
The 960 is very efficient with it's hardware specs, having a 128bit memory interface. It's good for Nvidia, highly profitable- bad for you.
The 380 has a 256bit, and GCN 1.2 has the same color delta compression that the 960 has. It's also very efficient due to that. The 380 is an unbalanced card it has way more memory bandwidth than it needs, today. This bodes well for the future though. The 960 won't improve nearly as much over time. The consoles using GCN will also help your Radeon over time.
There's many reasons like these I'd get an R9 380. It'll do more than you need today (which never hurts), but is the perfect chip for VR. Add another one in Crossfire in 6 months and you'll have a much better VR setup than dual 960's, I promise you that.
This is exactly my own plan. I was recently in the market for a video card, and got the R9 380. Tom's agrees-
http://www.tomshardware.com/reviews/gaming-graphics-card-review,3107-4.html
edit to add-
https://www.youtube.com/watch?v=j4xDfEOGONw LinusTechTips reviews the R9 285 at 4K in games people actually play. Rather than just benchmark. So you'll have more than enough for VR if you end up buying 2 of these. The R9 380 is the refresh of the R9 285 used in that video.