It depends on what you will be using it for.
Do you play fast paced games, like first-person shooters or racing games? Then 1ms 144hz+ is good.
Do you play strategy games like real-time strategy or turn-based strategy? Then IPS, probably 4k is good.
Or do you not play games, and use it for work or media editing? Then an IPS monitor would be good.
The reason as to why I ask this is because some monitors lean towards "fast and smooth" and other monitors lean towards "colorful and HD". Not many monitors do both, and fewer monitors do both well.