Minolta or Tokina 75/100-300mm?

I currently have A700 which I got like a week ago. I got Minolta 35-70 with it. Now, I got contract to be photograph for football club, but I would need good zoom lens. I would take pics of other sports also and overall. I got few options. Two that caught my eye are Minolta AF 100-300mm F4.6-5.6 with lens hood and Tokina AF 75-300mm F4.5-5.6 with both priced at 50ish€. Another option is Sigma UC 70-210 F4-5.6 but like zoom is much smaller and I would want more zoom than lens. It would be useful. There is like Tokina AF 100-300 but F5.6-6.7. What do ya thinks best? In short, best of these for sports photography.