[Ivor K Ecks]

Beside the aperature and the focal length it isn't any better then the kit lens

I am sorry , but i would have to completely disagree with that statement. I think the Sigma 17-70 is better in all departments. It is sharper throughout the zoom range, the close focusing ability is very good. The contrast and colour are very good and it focuses reasonably fast and accurately.
My copy shows very little if any vignetting and no zoom creep. It is my everyday walkabout lens and i couldn't be happier with it

[omega leader]

I've got one. It's a good little lens.

It's main advantage is it focuses very close, this coupled with the wide focal length allow for some very impactful shots that are physically impossible with the alternatives.

It is best at about 24mm to 32mm and is sharp and quite contrasty there. I have quite the selection of other lenses, but if i'm going somewhere with friends (i.e not photo people) I will take this lens.

Its heavy which allows you to hold it steady, but not unmanagable. It balances well on most of pentax's bodies.

I've been thinking of selling mine for every, as I have lenses that are better than this, (wider, sharper or faster), but none match the versatility so it's still here.

[creampuff]

Sharp enough? The Sigma 17-70mm is such a versatile lens, perfect if you can only use one lens.