Macro lens - Your Suggestions.

Hi Guys,

I am planning to buy a 'Tamron AF 90mm f/2.8 Di SP A/M 1:1 Macro Lens for Pentax' to experiment my skills on Macro.

Though I have read the reviews in Amazon, I need you guys help to decide on this lens.

1) I have a pentax K-x. How good is the AF of this lens with my K-x body?. Has any one tried it?.

2) Have you guys found any problem with this lens or Do you have any good suggestions?.

3) With f2.8 it should do good for portraits. Has any one tried? and If yes How are the results?.

I always come to this Post seeking for the experts advice before I get any gear. I decided upon K-x/Battery/50mm SMC lens after the debate here.

So, need ur help on deciding this too.

-Srini