hmm it must be strong point too, I just my 'join date' mar 2007. I sold my 2nd sigma 70-200 in jan 2007 for various reasons including the fact that the macro version was overdue at the time ...
I was looking to get the Sigma over the Tamron but it lookes like the IQ is much better with the Tamron. So its the Tamron. Hope the AF is better on the Pentax body though.
It's going to be a few months though for me due to the couple recent purchases. Maybe a review will be out by then.