What are the best 4k IPS monitors over 30"?

[CostcoSamples]

Monitor will be used for general office use and gaming.  Low input lag, IPS, and decent response time is required.  Any suggestions?

[Tsutae]

For AMD cards;
Samsung U32E850 - 31.5" PLS with FreeSync [40 - 60hz range].
Review: https://pcmonitors.info/reviews/samsung-u32e850r/

BenQ BL3201PT - 32" AHVA [supports FreeSync with a refresh rate of 48 – 60Hz according to users. BenQ did not openly advertise this.]

Review: https://pcmonitors.info/reviews/benq-bl3201pt-bl3201ph/


For Nvidia cards;
Acer Predator XB321HK - 32" IPS with G-Sync [Not yet released.]

PS: These are all UHD monitors at 3840x2160 and thus not true 4k.