How does the Samsung NX1000 compare to Nikon D5100?

I have the DSLR cameras Nikon D5000 and Pentax K-X, and trying to update with Samsung NX1000 or Nikon D5100. I prefer D5100 for using the same lenses as D5000 but also prefer NX1000 for the small size video ability feature and the lower price.

Your instinct to go for the D5100 is well founded. This tool explains why
http://snapsort.com/...ung-NX1000

Here are the specs, side by side
http://www.dpreview.com/...ung_nx1000

Notice that both cameras shoot 1080p video.

Very badly.

If you go with the Samsung NX1000 you will lose some image quality at high ISO. At or near base ISO, you won't see much difference. You also lose fast phase auto focus.

If a compact form factor is more important, skip Samsung and look at the Sony NEX line. The NEX 3N is the best value for the money. The NEX 5R adds fast phase auto focus.

Not another system!

You already have two different systems, Nikon and Pentax. Now you are about to add micro four-thirds into that mix?

Why update? What's missing with the D5000 and K-x? Did you know that lots of K-x users haven't seen a K-30, K-5 or even the equally old K-7 yet? That's because whatever camera is used, you get exactly the same pictures if you know exactly what you are doing.

Now, since you have spelled out video as your prime objective, I believe one of these would be a far much better purchase.

http://www.bhphotovideo.com/...order.html
http://www.bhphotovideo.com/...ng_hd.html