Tokina 80-200 2.8

[Okipentax]

I have considered purchasing the Pentax 80-200 2.8 for a while now, but the $1350 
price, while I'm sure fair, isn't pocket change. Tokina's 80-200 can be had from the 
NYC dealers for about $599, and there is a $60 rebate available, bringing the cost to 
$540 or so. My question is this: Should I save the money for the Pentax, or get the 
Tokina. I have always steered clear of third-party lenses, but I have heard good 
things about this one, and the price is right. Any thoughts? Thanks, Pete.