You can get a very good 240Hz TN screen for like $150.
TN screens are cheap, because they don't have the kind of contast-popping colors as IPS that survive lots of sunlight exposure (like on recent Iphones etc.) and they are easier to manufacture. Good old TN tech has been around longer and is still slightly superior for gaming, because they update faster and cleaner at same refresh rate. However with expensive quality IPS screens, the difference nowadays has gotten rather small, and it is simply a matter of paying $150 for TN or whatever $400 for IPS to mostly match refresh quality. The industry has been shifting away from TN and towards IPS, so over time IPS will probably outpace TN in specs. I have a 165Hz TN monitor and in my opinion the colors are excellent. But I have to use shades on my windows and point the monitor away from the window, as it has been for decades, or else it would suck to look at it. With IPS of course you got the same problem, but it is mitigated somewhat. TN panels also have narrower viewing angles ... however those "narrow" angles are actually gigantic-enormous if you compare then to 2010 TFT screens. It is basically impossible by a huge margin to hit them if you are sitting in front of the PC.
As of 2020, there have been lots of other technologies, none of which are viable for gaming, even if advertised as gaming monitors and having this and those specs. You pretty much want cheap TN or expensive IPS only. Or you could end up with something really awful, like a VA panel. I don't think this has changed in the last 4 years (actually OLEDs are now emerging, don't know much about that other than that the price is astronomical - so not worth it). TN is almost always good even if dead-cheap from reputable brands. But with IPS you can't buy cheap and need to invest time to study reviews and proper lab tests of the specific monitor you are buying. If you don't do this, then buying just "whatever" IPS screen is a huge risk. You could pay $300 for just a 144Hz panel and the update quality is worse than 90Hz or mostly parallels 60Hz. People are stupid, do stupid reviews. You need lab testing to actually know how good it is.
By rule of thumb, each time you double the refresh rate, you get only half the benefit for gaming. That is, going from 120Hz to 240Hz will only be half as good as going from 60Hz to 120Hz. I would say for Quake/Xonotic, you really want a minimum of 100Hz, which is what good old CRT monitors provided. So with a 60Hz monitor the game kind of sucks and you can feel it. While a 144Hz screen will not steer bad feelings. And 240Hz or more will still give pro players a considerable advantage and make the experience smoother still. But for casual playing, it is nowhere near as dramatically important as getting above 100Hz at least. I don't think they sell 480Hz yet at a reasonable price. But if they did, I would rather buy a faster TN panel for the same price as IPS at half the speed or a bad quality IPS at (allegedly) the same speed. Next thing you know, 500Hz and 1000Hz is the new normal. And 5-10 years down the line, you got a brand new PC and all that, and your 165Hz or 240Hz screen seems kind of outdated.
Ah yes, lastly I forgot to talk about screen resolution. From a functional and gaming perspective, if you keep your head at a reasonable distance of 50-80cm to the monitor (as it is recommended and normal when either sitting or leaning on desk), and your monitor is of normal size, then 1080p is and always will be enough resolution. It looks totally crisp and not objectionable at all. However at 50cm distance, you can probably go up to 4K and still perceive an small increase in fidelity (insofar as that you have excellent eyesight like me). But this is a really tiny difference, it is not worth it mostly. And unlike refresh rate, it is totally irrelevant for you gaming performance. 4K maybe makes a lot of sense for huge TVs and like image-fidelity fetishists, but not really for normal-sized PC monitors and normal gamers if you think about it. The tradeoffs are just not worth it. 4K monitors only make sense if reasonably large, and used for stuff other than gaming. Like a sort of compromise for multiple issues, such as being short-sighted and glued to the screen too much. Or doing a single or only dual monitor setup, when you really would fair better with 3 or 4 screens instead, but still want to use your PC as TV on the couch. Stuff like this. Don't buy 4K because it is "better", it is not. It only makes your games slow.
