I was questioning this for a long time ago and pulled the pin and went 144hz 2 days ago. Note i play csgo 95% the time i play games. For games that can run it, it feels so smooth and it is so much nicer. In cs, im not kidding, sniping/awping and one tap headshots are easier especially when you make fast flick shots and that. I came from an ips and for the first hour i had to play around with picture settings to get used to it (using a benq 2420z) but its fine now. Oh and the monitor is easier on my eyes.
If you play competitive games at 120fps and higher, yes its great and you should do it.
If you play demanding games, less competitive games (e.g. bf4) and cant hit near that, or gaming isnt huge to you then i would go for an ips monitor.