i'm up for VA panel instead, although IPS is fine, VA picture quality is mid-way between TN and IPS so its not bad, VA even has better static contrast.
VA has a slightly better response time than IPS, so it should be able to hit stable 120Hz if ever.
although 120Hz 4K is ridiculous, since its a part of setting out for long-time keeping might as well get a good one, and its not like you cant run a 120Hz monitor at 60Hz or so.