John,
I'm glad things worked out for you.
When I was deciding on an upgrade for the kit lens, it came down to either the Sigma 17-70 or the Tammy 28-75. I chose the Sigma because of the greater zoom range and closer macro feature. I've been happy with it, but wouldn't you know that that dad-gum 28-75 is still calling my name! Maybe it's the constant f2.8 or the IQ that's on par with some primes.
...sigh...
The 28-75's voice started getting louder when I decided that the DA12-24 will be my next lens purchase, as the 12-24 and 28-75 would make a nice pair of constant zooms.
My only concern is that I would miss the 17-28 range on the Sigma if I went with the 28-75.
If Pentax had made the DA17-70 a constant f/2.8 instead of f/4, that would've made things a lot easier for me.
There is the 16-50 and the Sigma 18-50, but 50 isn't always long enough for me on the tele-end.
Oh well...sigh (again)...
Heather