Nikon 18-200 vr2 or tamron 10-20 and tamron 28-75?

I have a Nikon 18-200 vr2
I just bought a 70-200 vr and it it much better than the 18-200
I wanted to know from anyone who has the lenses,
Is it worth it to sell my 18-200 vr2 and buy a tamron 10-20 and a tamron 28-75.
The 28-75 is a 2.8 so it is better than the nikon 18-200, and the 10-20 has a -8mm wider angle than the nikon so it will be better for landscape and wide angle.
I can't afford the Nikon 12-24 and 24-70 lenses because they are almost $2000 each.

Visit this site and see which focal lengths you like the best.

http://imaging.nikon.com/...simulator/

Yes.

Simple answer. Superzooms are cheap and terrible quality. I'm unsure how good the Tamron 10-20mm is but I know the Sigma 10-20mm is great value for money. The Tamron 28-75mm is a lovely lens, it being an F/2.8 should be reason enough to get it. F/2.8 should be as slow as you go if you want to maximise your image quality.