The portability of the Q system is still hard to beat. I carry a 01, 02, 06, and 08 plus a couple batteries in a case the size of a small book. My employer has had me travel to our different branches where we have plumbing showrooms and since the Q system has been so small and light, I decided to throw the case into my carry on and took pics when I had time.
I've found the 08 and Q7 to be a great architectural photography kit. It's not as wide as the 8-16 Sigma on a K3, but it's also way easier to travel with and 8mm even on apsc, is often so wide that perspective distortion often makes things look a bit too stretched in the foreground. Really, the coverage of the 08 is great for interiors. And the depth of field is so easy! Plus being able to easily handhold the camera and having effective shake reduction made using this camera simple. I was trying not to go past iso400 in case my company wanted to use these in other promotional materials and this highlighted the biggest limitation to the Q system. With the k5iis, I'd be comfortable at 1600 and 3200 w/ the k1 for this type of usage and this would make a big difference when taking pictures that were not well lit. Fortunately, most of our showrooms have pretty good lighting so the Q7 was fine.
Since the Q has a hot shoe, I eventually want to try out the Q7 w/ a full blown off camera flash set up to see how far it can be pushed. Will post those here when I get a chance.
Anyways, please share your architectural shots on this thread if you have them.