I've never heard of Zuikos being prone to fungus and so far, out of five lenses, 100% have been fungus free. I'm sure fungus happens to any lens that isn't treated right, but find it hard to believe that Zuikos are more prone to it than others. That must have been an aberration.
When I decided to go 100% film, my intentions were to stick with Pentax since I already had several lenses, started with a K1000, then went to digital with the K10D for a couple of years and then the K20D briefly. I was leaning heavily towards an LX and still think they are great cameras. I love Pentax, but I got much more for my money with Olympus, and without sacrificing any quality.
Also, there's just something about the OM's that really appeals to me. After all, the OM1 was truly revolutionary when it debuted, and though I also have an OM2, I find myself using the OM1 most of the time when I know which lens I'll be using the most. I still like the two camera/ two lens approach, so I do use them both.
Anyway, you just have to use what works for you whatever it is. I know not all my decisions are rational ones. Sometimes they are aesthetic, sometimes emotional, sometimes whatever. Often the rationalizing comes afterwards to justify my decisions! However I decided, I'm happy with my OM's and my Zuikos. I'd also be real happy with Pentax gear and Zeiss, especially if anyone wants to make a large donation! 😀