Sigma lens for Nikon d5100?

I was wondering how the Sigma 70-300mm f/4-5.6 SLD DG Macro Lens fits the d5100? And if it does, how does it cooporate with the camera?
Last, is it a good lens? Any downsides with it?

Sure it will fit if you get the Nikon model.

It will not autofocus on that camera.

Sigma calls lenses that have a built-in focus motor (like Nikon AF-S) HSM. If the lens doesn't have HSM in the name, it won't AF on your camera. Everything else does work properly.

The APO version of the lens is the best (cheap) 70-300 on the market. Better than the Nikon or Canon low end models.

You can use normal zoom lens is better.