sigma 10-20 VS Tamron 10-24

In the next few days I'm going to make a purchase for my next camera, and due to the size of the D700+lenses it looks like I need to stick with DX for a bit longer.

So one of the main cameras I'm looking at is the D300 for its resolution over my current fuji S5, but the one thing I am missing for my Nikon system is a super wide angle and I've narrowed it down to these two options, so any comparisons would be great