$600 for the display if you buy it from someone like Dell.
However the same display can be imported (guaranteed 100% pixel perfect- something Dell nor Apple will do) for around $300.
Actually, the $350 Korean displays are based on the same LG panels as Apple and Dell's displays, but they use the reject panels that Apple and Dell refused. They also lack a fair amount of hardware that the more expensive displays include. This makes them great for gaming and over-clocking, but not quite as good for professional color work.
Saying it has a 2-port thunderbolt controller is a bit misleading. It has 1 usable thunderbolt port. The other will be plugged into your Mac.
I'd maybe pick one up if they had thrown a couple of eSata ports on it, but its not worth it for the price. The henge rMBP dock is out soon with any luck, and whilst it comes with (optional) thunderbolt pass through, it also offers 3 MiniDisplayPort video out ports, 6 USB 3.0 ports, 1x Firewire 800, 1x Gig Ethernet, SD card and left/right audio outputs. For $249 ($349 with passthrough) its a way better option IMO.
It isn't misleading at all. To be even more specific, it contains a 4-channel, Intel DSL3510L, or possibly even one of the newer DSL4510 controllers. I think most reasonable people understand that single port devices are chain enders, and dual-port devices allow further daisy chaining or display output. Both ports are 100% usable.
The Henge dock you're looking at most likely contains:
2x VIA Labs VL812 4-port USB 3.0 hub controllers
DisplayLink DL-3900 dual head USB 3.0 display adapter with 6-channel audio and GbE MAC
Intel DSL2210 single channel (PCIe only) Thunderbolt controller or possibly a DSL3310 dual-channel (single port) controller for the MBA models
FireWire 800 host controller
USB SD card reader
Which actually works out to being a way more compromised system for the money. It only works with the specific model of MBA* or MBPR that it is designed for. Two of the DP ports output a compressed signal fed from a single USB 3.0 port along with the Ethernet and 3 of the USB 3.0 ports. Thunderbolt passthrough is not possible without paying an extra $100 for a 2-port Thunderbolt controller. It blocks all of the ports on your Mac, and the provided USB card reader is most likely not as fast/capable as the UHS-I SDXC reader that comes built-in. The power situation is not clearly illustrated, but I imagine relies on using the adapter that came with your MacBook or buying an additional Apple power adapter.
edit: eSATA is a far less appropriate consumer device interface and mostly pointless now that we have SuperSpeed USB.
*I am also relatively certain that these docks will only work with 2012 MBAs, and are not capable of adding USB 3.0 to a system that does not ship with native chipset support. The feature set and system requirements for the MBA version were not explicitly stated however.