A PC is generally better for gaming, especially if you invest money in the hardware. However, because PC hardware advances every year game developers pushes the performance envelope which means new games will require higher performing hardware as the years progress. A GTX 970 is a very powerful and expensive graphics card which should last you a while before you feel the need to upgrade again. The higher your performance expectations, the sooner you will feel that that GTX 970 no longer is good enough.
The hardware in consoles is basically locked. It will not change until the next generation is released whenever that is. Because the hardware never changes, game developers cannot push the envelop too hard because if they do, then the game designed to run on a PS4 or Xbox One will not be able to run well. Assuming game developers do not release poorly optimized games for the console, a PS4 / XB One game released in 2020 for the console will be able to run on any PS4 / XB One console regardless if you bought that console in 2014 or 2019. And everyone's experience will be the same on the same console. You will probably still be able to play games in 2020 with a PC you build / buy in 2014. But performance will not be as good compared to a PC with newer hardware.
While PS4 / XB One graphics may look fine now, by 2020 they will definitely not look as good as the graphics in a gaming PC built / purchased in 2020. You need to decide what is more important you.
#1 - Cost - If you want to keep cost low, then buy a console because there is nothing to upgrade. Unless the console fails you really only need to spend money on games.
#2 - Graphics & Performance - If very high / ultra graphic settings are important as well as high frame rates, then go with the PC. Be aware that in order to maintain a certain minimum performance in PC games you will eventually need to spend money to upgrade the hardware. The higher your expectations the more money you will need to spend.