I do think that a lot of this has to do with what you are used to using. I prefer the K1000 and the LX, I think because I really started with the K1000 and moved up to the LX later on. Although I feel that they are both terrific cameras, I am not sure it is because of their design, which I am probably not qualified to judge anyway.
I have tried a number of other cameras, and I like them as well, but these two have been very reliable for me so I continue to return to them, especially when I feel I "need" to get some shots, such as birthdays, weddings, etc. Since they continue to bring home the goods I continue to prefer them, kind of a positive feedback loop. I am probably at the point now that, even if one or both were to break down, I would just ignore it and move on, having them repaired without a second thought.
However, I know that not everyone has this experience with the Pentax cameras. Some have similar experiences with Leica, Canon, Nikon, Minolta, etc., so those are the cameras they tend to prefer. Some have tried Pentax and had bad experiences, or at least have not found them to be "just like their" _________ (fill in the blank with another camera.)