Tamron SP 90mm F/2.8 Macro?

I using Nikon D90 and want to buy a Micro lens… I just come across this lens, want your view on this or you can suggest me if any…

The Tamron will easily out-resolve your sensor. To be honest, it's really really hard to buy a bad true macro lens. Every macro lens is designed to deliver absolute sharpness at close-focus range, and because they are relatively specialized lenses, manufacturers assume that those who want them don't want to waste their time with poor quality optics. The offerings from Canon, Nikon, Sigma, Tamron, and Tokina are all basically the same as far as optical quality -- I'm speaking from experience because I have used every single one those and they have all delivered acceptable image quality with nearly imperceptible differences. There are very slight differences in color casts and contrast between lenses, but that's a matter of preference and there's no objective "Better."

The 105mm f/2.8 micro-nikkor from Nikon is made by the company that makes your camera. It's more expensive, but you have the added benefit of using all original manufacturer parts (there's just something extra about have everything as designed). Plus, as the lens belongs to your camera system, it is more likely to be supported in future cameras. Tamron, Sigma, and other third-party lens manufacturers reverse engineer the electronic protocols for their lenses to fit a particular manufacturer, but it has been known in the past for these lenses to not work properly on newly released cameras.

It's affordable. It's optically a good lens, but most macro lenses are. I like the fact that you only have to pull the focus ring to switch to manual focus.

In the end I went for the 100mm tokina. The price was about the same but the tokina is build so much better than the tamron. If you can find the tokina for a good price that would be my advice, if not go for the tamron.