[1] https://www.google.com/search?q=HK%2441%2C899+to+usd&ie=utf-...
[1] https://www.google.com/search?q=HK%2441%2C899+to+usd&ie=utf-...
The ASUS PQ321Q (great product name, guys!) is offered at B&H Photo for $3,262 [1]. I'm a big fan of Dell's Ultrasharp line and have bought several over the past decade, but ASUS is winning this battle. That $2200 is almost the price of the low-end MacPro you're going to want to buy in order to drive this beast.
[1] http://www.bhphotovideo.com/bnh/controller/home?O=&sku=98636...
- A 4K monitor has less DPI than a "retina" monitor, so you still see the pixels, thus it's not like someone took a 27" cinema display and doubled the pixels.
- Two 27" displays feel 'worse' to me: While it seems like dual 27" displays would be able to display more, I can't use them both horizontally because my head has to pan too much. And if I switch them to portrait, it's hard to fit two editing windows side-by-side in 1400 pixels comfortably.
So I like the 4K better than the 27" (or dual 27") setup I used before.