I'm not going, cause I'm near JB. But if there is TT somewhere around JB I might be interested.

Well, at the moment the only 10-24 available has a nice scratch in the center of the lens... like a 3x3mm area that is scratched. The price is accordingly quite a bit below what you'd normally pay (and might bargain further), but... yikes. I wouldn't mind with a tele lens, but a UWA... Also I have to shoot into several bright lights at the same time, with a heavily stopped down lens. Basically exactly the conditions that make you see such scratches.

Yeah, the range is what interests me, I need the 10mm, but if I can use it as a walk around lens that'd be pretty cool. I'm fine with shooting at high f-stops, well, I have to anyway. Usually everything is supposed to be in focus. When walking around I'm fine with not so sharp photos. The 10-20 f3.5 is really out of budget, and I just need something that is sharp at f11. Build quality is nice, but... well, I can do without. The 18-55 kit lens has served me well. And also the Tamron is simply even lighter than the Sigma 10-20 4.5-5.6 or so... that's nice.

Haha, distortion won't work for me. I sometimes shoot interiors (which hopefully will pay for the lens ).

Alternative could be a nodal point adapter (right now I have to trick around to get huge panoramas where lines match, takes a ton of time, with that adapter it would be much faster). More flexible as I can shoot even wider, but nowhere near as fun as a UWA lens.

One disadvantage could be if you're the only one shooting Pentax you can't borrow lenses from others. But to be honest I'd feel uncomfortable using anyone elses lens, too scared to damage it. I'm the one treating a rental car better than his own car... But if you like the K-5 grip and feel, and like the buttons etc., more so than the competition, then that'd be what I'd buy. While I smile when I see the D7100 or 70D price, I would still have picked the K-5 if I had no other lenses and the cameras were the same price.

Btw. when I bought my K-5 the alternative would have been the slightly cheaper K-30. I've tried that in the shop too, but somehow it just didn't feel as nice as the K-5 to me. (The demo unit was painted blue, so maybe that made it feel cheaper). Also the top panel LCD was a big point for me. My old Pentax had that, and I used it. I didn't want my new camera to feel like a downgrade. Since you are used to the big boys from Nikon I'd suggest you to stay in the same class.