I visited a Tiger Direct store near by which had the $1300  Seiki 4K TV set up and hooked up to a gaming PC. I didn't know what to expect as I've heard good and bad things about it. 

http://www.tigerdirect.ca/applications/SearchTools/item-details.asp?EdpNo=7674736

Hour long unboxing and testing: http://www.youtube.com/watch?v=uXBu9nxLN78

After about 20 minutes of playing around with it at TigerDirect and testing certain things, below are my impressions:

1. It handles the following resolutions:

4K@30hz

1440p@75hz

1080p@120hz

4K@30 is perfectly fine for productivity and desktop but gaming isn't ideal at 30hz. Its still doable, infact I didn't mind it much, but I do notice a slight visual and input lag. 1080p@120hz input is amazing and this alone is worth this TVs purchase. 

2. Picture quality

As a TV, the picture is decent but not great. You can buy a 1080p TV for this price form Samsung or Panasonic that will demolish the picture quality that this TV offers.

In terms of a computer monitor however, the picture qiality is excellent and you would have to buy a very high end IPS display to match it.

3.  1080p to 4K scaler

Vor video sources - not bad. video looks slightly sharper with little visible artifacts. 

For PC and desktop - absolutely terrible. I am not sure if there is a way to turn off the scaling features when using PC mode and if there is, it would be an absolute must. 

Conclusion

Based on what you are looking to do, I would rate this TV in the following manner

Good Buy:

As a PC gaming TV (1080p@120 hz) this TV is awesome. As good as those 120hz monitors but with an IPS pannel that delivers a much better picture.

As a desktop and productivity monitor, the TV is big enough to be used at 4K resolution and 4K @30hz isn't an issue

Don't buy:

As a TV with little to no 4K content, this TV isn't a great purchase. Spending the same money on a 1080p set will deliver a better picture.

Gaming at 4K@30 hz is a no go

30Hz? Oh lawl.

Yeah, I don't think 4k was the way to go :/. Now if they made it like the retina displays, then I'd be for it. But when I saw Sony's 4k T.V. at the Sony Store, I saw the pixels. Very disapointing.

Why lawl? In terms of where majority of 4K content will come from, hollywood movies are shot in 24hz. You won't see over the air/cable 60hz 4K in the next 10 years...

At what distance though? 

3 feet back I doubt you will see pixels. 4K at 50 inches has roughtly the same ppi as a 24 inch monitor.

So if you move back 3 feet from a 24 inch monitor do you see pixels?

Ya......stick to 1080p for the next 5 years.

Been seeing 1080p Samsung 120h 60 inch TVs for $1300 if you know where to look.

i doubt ull even get 30+fps in games @ 4k anyway...

in other words you want a resolution that is vastly higher than 4k?

Yes =D

I was a few inches away.  I was just saying if you're going for a higher resolution than 1080p give me retina display pixel density.  It's not like at 56inchT.V. at 4k or 1080p will give you more details unless you're right in front.

In the end, you get what you pay for.

Other 4K TVs of the same size cost twice as much, so it shouldn't be much of a surprise to see that this TV isn't as good as it could be.

Thanks for the impressions!