They are about the same, excepting multiple GPU configs which most people don't worry about. Mostly it comes down to convenience, brand preference and what games and resolutions you are doing.
For 1080P gaming GTX 970 is enough and you will play games without any problems. I suggest you to buy GTX 970 and save some money and buy new monitor or whatever you want.
I believe you will be happy with a GTX 970.
Yeah, or just wait for a Polaris/Pascal card to come out. Even a R9 380 can do most stuff at 1080p and leave you $400 for a Pascal/Polaris card if you really need one now.
I second the recommendation for a 390 for 1080p. They tend to cost a little less than the 970 and will perform identically in most cases, with the 390 becoming better at 1440 and 4k resolutions