Don't waste your time on a reference GTX970. Just get one of these ones instead:
Read the reviews -
http://techreport.com/review/27203/geforce-gtx-970-cards-from-msi-and-asus-reviewed/6
GIGABYTE GTX970 Windforce -
http://www.guru3d.com/news-story/gigabyte-releases-geforce-gtx-970-windforce-oc-graphics-card.html
ASUS Strix GTX970 DirectCU II - http://www.guru3d.com/articles-pages/asus-geforce-gtx-970-strix-review,1.html\
MSI GTX970 Gaming 4G - http://www.techpowerup.com/reviews/MSI/GTX_970_Gaming/
Zotac GTX970 AMP Extreme - http://www.bjorn3d.com/2014/11/zotac-geforce-gtx-970-amp-extreme-edition/
If you want to look at all reviews - http://www.techpowerup.com/reviewdb/Graphics-Cards/NVIDIA/GTX-970/
The Gigabyte card is the highest Factory OC, has 3 x Fans, is the noisiest but has the best temps
MSI and ASUS are pretty much the same with regards to features, but the MSI is the better quality (Military Grade) - both have Fans off until 50-60degC is reached, the ASUS has a back plate, the MSI doesn't, the MSI has 2 of the VRM modules on the back with no active cooling - hence no back plate. The MSI is Factory OC'd higher than the ASUS.
Keep in mind i'm not including Gold, Black or Platinum editions here in this quick summary - just the cards marketed for gaming)
The Zotac - I've linked the wrong one just above - the AMP Extreme is equivalent to the Gold, Platinum and Black editions of the MSI, ASUS and Gigabyte, but I couldn't find a link to a Zotac GTX970 AMP Omega review which is essentially their Gaming level entry.
Read the reviews and work out what suits best, but seriously, don't get a reference card, spend the extra $50 for the quality. My recommendation is the MSI GTX970 Gaming 4G because I have one...and its just fantastic. I went for ultra silent in my most resent build...and succeeded! - I combined the ECO mode of the EVGA G2 SuperNova PSU with the MSI GTX970 Gaming 4G, I7-4690k OC'd to 4.65 (Turbo) and a Corsair H75 Liquid cooler - all of which are dead silent under 60degC. in Fact I can play Crysis 3 on Ultra with this setup (1920 x 1200) and the GPU doesn't get over 55degC, the PSU Fan doesn't turn on, and the CPU runs at about 45-55degC too so the Radiator Fans are still idling. Pretty happy with that considering its summer here in Australia and indoor Ambient is around 25-28degC
You'd get the same result with the ASUS, but I went with MSI's Military Grade build, higher Factory OC and Twin Frozr V's are damn good fans too. The Gigabyte Windforce was a looker with its superior cooling, backplate and higher OC - but its plasticky, reviews have it noisy at anything above idle, not silent (fan off) mode (which tells you their Heatsink isn't as good as MSI's or ASUS and they rely on the Fans to do all the work!). The Zotac's wee not available when I made my purchase, and still waiting on reviews.
All in all, all the cards there will be great - there's not really a wrong choice, grab the one that suits your requirements and budget.
Good luck, hope the info is helpful!