I have about 1000 hrs on the Pressurized Navajo, may be the worst of all.
I figured if I was here on Pprune long enough I'd run into someone else that flew a Pressurized Navajo. I don't have as much time in them as you, but I was happy to stop flying them. We had a lot of engine problems until we started using 65% power for cruise, the engines seemed to like 65-70% much more than 75%. Not to mention the Micky Mouse pressure controller system.
There is one sitting at a local airport here, the tires and struts are flat, but it is providing a nice home for numerous birds.
I really don't believe that there any still flying, at least I have not seen one, except the one I described above, here in the US and I never saw one when I was flying around Europe. Or the rest of the world for that matter.