Sigma 17-50 2.8 for D7000: The one to go?

I have the Sigma 17-50mm 2.8 and use it on my D7000. Here are my brief findings though others may have different ideas:

Sigma - sharpish in the centre but pretty poor at the sides and corners. However, the only lens to offer 2.8 in this category. I have kept it and use it most of the time on the D7000 (and D300s). Note that the lens hood lasted about a month before no longer fitting on the camera. Have since bought a third-party metal screw-in hood.

Nikon 16-85mm - roughly the same quality as the Sigma but no 2.8 and out of two copies I had, the zoom ring jammed on both copies and Nikon wanted paying each time (out of warranty). After paying £108 for the repair, I sold this lens (had already sold a previous one that I bought with the D300s).

Nikon 18-105 - I did not find this a very good lens. It was not at all as sharp as the above two. I took it straight back to the shop after a few tests.

Nikon 24-120mm f/4 - far and away the sharpest, putting all the above lenses to shame, especially in the corners. However, it's heavy and expensive, and doesn't go wide enough for most needs. I still have this lens for when I am looking for quality. It really IS that much better.

For really sharp images, I use the Nikon 50mm 1.8G and occasionally the 35mm f/2 which is great at f/8 (but pretty rough at wide apertures). The 35mm 1.8G is supposed to be good but I found it no better than the 35mm f/2 which I kept. Returned the 35mm 1.8G very quickly.

Just my experiences. Others may disagree or have had different experiences.