Why would you get the 290 when it gets hotter, it's louder, it has no features compared to Nvidia's card, it will overheat if overclocked? The 960 would be much more reliable and if you overclock it and your system it will beat the 290 anyway. With the 290 if you overclock it, it will overheat unless it has a good cooler.
Also will the 290 support Direct X 12? Can the r9 290 do games at 1440p and 4k at a decent fps?
1. 290 runs much faster than a GTX 960. (128 bit bus vs 512 bit bus)
2. The XFX Card I recommended costs the same atm, and has a lifetime warranty.
3. The R9 290 is known for being decent at 1440p/4K and beats out the 960 anyways.
4. Overclocking your GTX 960 will not get it higher than the R9 290 unless you win the silicone lottery.
Even with the 960's 4GB of memory, it can't fully utilize it with its smaller memory bus. Look at the R9 290 benchmarks. Also just saying, you can't run a GTX 960 in 4k. Frame rates are terrible. For the sale on the R9 290 it will mop the floor with Nvidia's cheaper GPU. Even the R9 280x beats out the 4GB card, in most games.
EDIT:
Just realized this is the 2GB model. That 960 REALLY stands no chance. The 4GB maybe, but definitely not the 2GB model.
Also average temperatures for this card are around 70C.
To answer your question, "Why would you get it?", I would buy this card if I was looking for good 1080p performance that outperformed the GTX 960 for the same price. The r9 280x beats out the same 960 and the R9 290 is 23% faster. If you are making a new PC, i'm guessing you don't plan on OC your GPU that much, but if you are the 960 still will not perform faster. It all lay within the hardware between each card. Let's break it down:
R9 290 GTX 960
GPU Bus (bit) : 512 GPU Bus (bit) 128
GPU Clock : 947MHz GPU Clock: 1178
Stream Processors : 2560 Stream Processors: 1024
Memory
Memory Bus : 512 bit Memory Bus: 128 bit
Memory Size : 4 GB Memory Size: 2GB
Memory Type : DDR5 Memory Type: DDR5
Clock speed isn't everything my friend, G'day m8.
Sources:
http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/65741-xfx-r9-290-double-dissipation-review.html
http://gpu.userbenchmark.com/Compare/Nvidia-GTX-960-vs-AMD-R9-290/3165vs2171