sigma or tamron 70-200 f2.8

please can any of you more knowledgeable people help me choose between
these two lenses.just bought k20, to go with k10 and sigma 10-20.thank you

http://www.dpreview.com/

Hi parker06. Been looking at these lenses myself, found good reviews at the above link

Hope this helps

thanks for that cliff.how true though, more letters = more confusion = more sales !!!