I have not seen any other zoom with the focus range of 80-320. Manufactured in the era of AF film camera, these zooms, especially the black ones that look more professional, are highly sought by Pentax users because they are fully compatible with both digital and film AF Pentax bodies.
I have used them in both colors. Although the black looks cool, it was heated up quicker than the silver one under strong sunlight. If you will use it mostly outdoor in summer, I recommend you to get a silver one. Your fingers will confirm what I said here.