In the end, they're all good enough for a good photographer and the right settings to get excellent photos from - Sigma, Tamron, Tokina, or the Sony branded ones. There may be a few advantages or disadvantages among the different lenses, but they all come pretty close to evening out in the end. The Tokina's the fastest, and respectably sharp, but suffers more flare issues, the Tamron is the next fastest and almost as fast, with very good flare control and center sharpness, but suffers a wee bit more corner softness when the aperture is wide open, the Sigma is slower but decently sharp in the corners and when stopped down, but has the hardest to correct distortion due to complex curving and bending only at the ends of the frame. The Sony is a Tamron design, and so closest to the performance of the Tamron, though the Sony is based on the older Tamron lens before the current 10-24.
I've been very happy with the Tamron 10-24 for many years now and would recommend it to anyone...but I also don't think you'll go wrong with any of the others.
Sony DSLR-A580 / Sony 18-250mm / Minolta 50mm F1.7 / Sigma 30mm F1.4 / Tamron 10-24mm / Tamron 200-500mm / Tamron 90mm F2.8 macro / Minolta 300mm F4 APO
Sony NEX5N / 18-55mm F3.5-5.6 / 55-210mm F4-6.3 / Pentax K adapter / Konica K/AR adapter / bunches o' Konica & Pentax lenses!