So, why is this the first 4K Ultra HD that I am listing as my "Product of the Week"? I hope you are sitting down, this baby is selling for less than $1,500!
Now, before you get too excited, let's see what this TV really offers. Besides a native 4K screen resolution, the specifications include a 120Hz screen refresh rate, and 5,000:1 native contrast ratio, so that means that you should see good motion response, but probably not those deep inky blacks that can really give color that extra pop. Also, although it employs LED technology, it is not stated whether it is backlit or edge-lit.
As far as inputs go, the Seiki SE50UY04 provides 3 HDMI, a VGA-PC monitor input, a combined component/composite video input, and the now rare headphone jack that is great for late night private listening.
On the other side of the coin, here is what you don't get: No Smart TV features, and no 3D. Also, there is no indication whether Audio Return Channel is supported (Update 4/30/13: After making an inquiry, Seiki stated that the set does support ARC).
Another factor to take under consideration is how much of the benefits of 4K resolution, as opposed to 1080p resolution on a current LED/LCD or Plasma TV at a 50-inch screen size, that may be selling for the same price or less - with either 3D or Smart TV features or both. Also, how well does the set upscale 1080p or lower resolution sources to its 4K display resolution? One practical use for the set might be as a 50-inch 4K UltraHD PC monitor (30Hz support).
For some additional perspective on the Seiki SE50UY04, and how it fits into the consumer TV landscape, also read reports from Dealnews, PC Perspective (article and video), PC Magazine (review), CNET (review) and Consumer Reports (review).