Is it true that the difference between a 1080p monitor and a 1440p monitor feels much bigger than the difference between a 1440p monitor and a 4k monitor?

I was talking to a friend about it. I was split between a 1440p monitor that was more powerful or a 4k monitor and my friend told me that I probably wont feel a difference and should go for the more powerful 1440p monitor, since the amount of MHz is more important.