Quick answer.
This card:
http://pcpartpicker.com/part/evga-video-card-04gp42974kr
1) Free games?
I'm not aware of any currently running promotion, just the price drops for R9-290 and R9-290X
2) $50 diff?
Yes, if comparing an Asus R9-290X to an EVGA GTX970. While that's fair, they are NOT equal in performance.
3) Performance diff equal?
No.
http://www.techpowerup.com/reviews/EVGA/GTX_970_SC_ACX_Cooler/25.html
Over 20 games a stock GTX970 is 7% faster on AVERAGE. We also know the GTX970 overclocks a bit better so let's say at least 10% faster...
Oh, and the GTX970 supports MFAA (for anti-aliasing) which can boost frame rate even more (varies a lot). Let's say 5% to 20%.
4) GTX970 other stuff:
- quieter
- can DISABLE FANS for no noise (not all models. Gigabyte does not I believe. EVGA does.)
- HDMI 2.0 (4K at 60FPS)
- H.265 hardware support
- vox light (for future games)
5) *GTX970 memory issue:
I must mention this. Yes, it can cause stutter if a game uses more than 3.5GB. That's currently a very small minority of games. There's also a probable fix for this coming despite NVidia saying no current driver fix coming.
I expect the worst-case scenario will be an option (or done automatically) to force only 3.5GB usable of video memory to avoid the slow 512MB memory.
Summary:
I highly recommend the EVGA GTX970 SC 1.17GHz ACX 2.0 model:
http://pcpartpicker.com/part/evga-video-card-04gp42974kr