Kind of a pointless question.
Obviously the 980 is more powerful and is hence more expensive compared to the 970.
If you're on a budget build and is looking for some great 1080p gaming, get the 970.
If you have money to spend and you're looking for something that will be able to run all the games pretty well for the near future, get the 980.
If it were up to me though, I would get the 970 in SLI instead of the 980.