Important question

Get both if you can. They are two different lenses for different purpose. Similar to Sony 70-200G, Minolta 80-200 APO HS has fast focusing speed, great colour and sharpness. Its constant f2.8 will prove to be more useful than you thought. Think of low light, high shutter speed (sports), the ability to add teleconverter, of course it's a great portraiture lens too. Tamron 70-300 is just a cheap lightweight consumer lens that's good for landscape, travel. I have the Tamron and Sony 70-200G, and like them both but use them for different purpose.