IT IS ALWAYS A PERSONAL CHOICE. No one can see 144 frames per second. No one can see 60 frames too. Hardcore gamers will say to go for 144 Hz monitor, that too when deciding between two while in the state of purchasing. But you already have a good monitor, upgrading will not give much difference. GTX 970 will make 60+ fps in almost all games at high settings and you'll have 60 frames per second from both your monitor and GPU. You'll never have any stuttering or screen tearing in games. With higher refresh rate monitors you might face these issues. Stick with what you have. But 144 Hz can be downscaled to 60\ Hz. See, it's again comes down to personal preference. If you have money, try buying ASUS ROG PG278Q 😀