Lens Recommendation for Nikon D7000

[Black Tea]

I have chose to get the D7000 for my brother in law in Ecuador.

I see the AF-S DX NIKKOR 18-200mm f/3.5-5.6G ED VR II Lens for $598.

Anyone have a suggestion for a better or as good Sigma or Tamron?

Would an 18-270 be better?

Thanks