Please do not take this as a rude comment as I'm really not trying to be rude, but how does somebody who's been working in graphic design and the like not
know what an IPS display is?
IPS panels are known for high color accuracy and wide color gamut, or rather "vivid colors" ect. The reason you like the Apple display so much is because it's going to be an IPS panel. These are expensive panels mainly aimed towards people like you (actually). Thunderbolt is irrelevant to the quality of the panel just for clarification.
You're used to a TN panel which are cheaper and aimed more towards the mainstream crowd. You have higher end TN panels that are aimed towards gamers which is where you'll find higher refresh rates and lower response times.
Since 4k hasn't matured, your options are still pretty limited. For instance, one of the only IPS 4k panels Newegg has is 2k.
Dell UltraSharp UP3214Q Black 31.5" 8ms HDMI Widescreen LED Backlight LCD Monitor IPS 4K 50 ~ 300 cd/m2 2,000,000:1 - Newegg.com