Tamron Lens good as Nikon?

I have seen them on ebay 18-200mm for £160 and Nikon 18-200mm for £550-600 and that's over price, expensive and wasn't sure if tamron is actually good company and trsuted? Are they good for Nikon camera?

They are not as good as Nikon - especially that lens.

In the aftermarket, the best lenses are made by Tokina, then Sigma, and Tamron taking up 3rd place. You get what you pay for.

No
I wouldn't buy a Tamron lens - Tokina or Sigma if you can't afford Nikon.

No. I own an 18-200 and it has focus and aberration issues. Buy Nikon.

It's the 18-250 or 18-270 Tamron you need, they are a lot better.
Generally Nikon's own lenses, even if secretly farmed out to trade manufacturers like Tamron, will be made to more exacting quality standards.

I've had several Tamron lenses over my 40 odd years in photography. I still have and use often a Tamron SP 90mm f2.8 Macro and 500mm SP Mirror lens. The Tamron SP are the better ones.

Nikon lens are far better.

Camera maker branded lenses are usually the best option for a given camera. Nikon optimizes their lenses for their bodies so it is, almost always, the best lens for the job. That being said, sometimes third party manufactures make a lens which is so good it rivals the maker branded lenses.

On this lens, the Nikon is the best option by a long shot. I bought my mother a D7000 for Christmas a couple of years ago. Before buying her a 18-200 lens I tested several brands Nikon, Sigma and Tamron. The Nikon came out heads and shoulders above the other makers lenses.

If you want the best you have to pay the price. The price might be high but the Nikon is the best lens in the zoom range you want.

No.

Most often not at the best. There are some rumors Tamron made a mistake and actually produced one that's really good but I don't know which one.

http://keerok-photography.blogspot.com/2011/05/third-party-lenses.html