[davidmanze]

The AF felt Ok to me but then it's a 20mm lens.

 

If there are AF problems you can tune all this with Sigma's USB dock so I'm not sure whether this is a killer argument against these lenses. Sooner or later you will have to get one anyway if you plan on buying multiple Sigmas. Every once in a while you will stumble across firmware updates anyway (which can be good thing - e.g. the improved AF on the 150-600mm).

 There is no doubt that there is an excessive number of complaints about their recent lenses, to site one review from Pentax Forums, they gave up on the first attempt and recontacted Sigma,.......here's their second attempt....... 

 

http://www.pentaxforums.com/articles/rev...-look.html

 

   While many buyers have returned their Sigmas and gone elsewhere, some of them having been "driven mental" with AFFT with their docks........ others seemingly have never had a problem or even noticed one!

 

 Like it or not,  it's an ongoing complaint..........not only with Pentax which has a small sales base of this lens but more generally with Nikon......I don't follow much in the Canon world.