Originally posted by Edvinas How do you know that? And what has QSF has to do with AF speed? When AF works properly, you don't need QSF anymore anyway.
Educated guess.
QSF allows for more creative control, and, can be faster when your camera becomes an extension of your eyeballs. Marginal spec. differences are irrelevant if you know your camera intimately. I'll be taking pictures with, and learning how to use, my K-7 when you're waiting for your larger, bigger camera to arrive.
I once read, and do believe, that switching camera brands means that you lose 6 months of top productivity while you learn the peculiarities of a new system. From Pentax to Samsung I would expect that to be much shorter though. But, the menuing will be different.
Every time I buy non-Pentax equipment I end up regretting it. I have only Pentax lenses and view the combination of the entire 'system' to be more important than specifications. Even if the Samsung camera specs better, I don't care because the gestalt just won't be there. Horses for courses...