Nikon 55-200 VR or Sigma 18-200mm? Which one is better?

I'm using a Nikon D3000. I would like to take portrait and landscape pictures with a good quality. Which one is better? Sigma 18-200 is much more expensive than Nikon 55-200 VR.

I think Nikon 55-200 VR

I prefer an 55-200mm lens. I tired a 18-200 and it was too heavy to lug around for any length of time.

I also added a Tiffen warm/soft FX3 filter ($48.00) for portraits to cut down on the sharpness of the lens.

And of course used wider lens openings for portraits.

The 55-200mm is the better lens optically, it's also smaller and lighter than any 18-200mm on the market, and an ideal complement to your 18-55mm.

It's no hardship to change lenses when you need to, or to slip the lens you aren't using into a pocket.