Originally posted by Nass interested_observer - very good point. Although there's a certain 'cachet' with the Pentax stuff, I wonder if the sigma 10-20 is really "SO" awful
The Sigma 10-20 is not "so awful" at all. Many Pentaxians - highly experienced and relative newcomers - are happy owners of the Sigma 10-20mm f/4-5.6 lens. If you haven't yet... check out the Sigma 10-20 Club message string:
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/84539-sigma-10-20mm-club.html
I currently have all Pentax glass in my kit. And while part of me would really like to keep it that way, I find it very difficult to spring just over $700 (street price, U.S. dollars) for the 12-24... while the Sigma 10-20, at well under $500, can give me the kind of images seen in the message string above. The Pentax is a fine lens but the Sigma is no slouch either - and represents much better value. Just make sure you go for the older f/4-5.6 version, not the newer, more expensive f/3.5 version.
There is talk of a new ultra-wide angle Pentax zoom coming soon - possibly a 10-16mm or something in that area. While that would be great, I've seen nothing yet. And people have been begging for a Pentax-branded version of the Tokina 11-16mm f/2.8 for years - to no avail. For that reason, I'm not holding my breath. There are a few photo shows due in early and mid-March (mostly in the U.K. and Europe). If Pentax has nothing meaningful to announce at those events, I'd buy the Sigma and never look back.
One caveat: With the very latest Pentax DSLRs - i.e. the K-7 and K-x - there is a setting that minimizes distortion when used with Pentax DA and D-FA lenses. If that's important to you, then go for a Pentax lens. But I've read posts that say the anti-disortion program is not that dramatic - and even works with third-party lenses (although theoretically it's not supposed to). Perhaps some Pentaxians who own those cameras can fill us in. Good luck.