1920x1080 vs 2560x1440

Solution
Been using a 27' 1440 for the last 5 years at work, and I can never go back to anything lower.
For games, however, 1440 has ~80 more pixels than 1080 which will reduce your fps by 80% given the same settings.
The higher rez is obviously less noticeable in games IMO.

The question you'll have to answer is which do you prefer:
-Lower resolution at max quality.
-Higher resolution and lower quality.
-Spend significantly more on gfx and have both.
Been using a 27' 1440 for the last 5 years at work, and I can never go back to anything lower.
For games, however, 1440 has ~80 more pixels than 1080 which will reduce your fps by 80% given the same settings.
The higher rez is obviously less noticeable in games IMO.

The question you'll have to answer is which do you prefer:
-Lower resolution at max quality.
-Higher resolution and lower quality.
-Spend significantly more on gfx and have both.
 
Solution
Also. Unless you spend $800 for the Asus Swift, and $1200 for the graphics solution to run it, you can't get 1440p with a high resolution natively.

I have flagship monitors from the best brands in both 1080p, 120Hz, and 1440p, 60Hz IPS. For gaming, I pick the 120Hz monitor nine times out of ten; the higher pixel density doesn't matter when compared to the smoothness of the faster monitor.

Also, a lot of content is far worse at 1440p. There's a lot of stuff out there not designed for it, that either breaks or just doesn't go to a high enough resolution and so looks awful.