My previous employers used to operate a 6000-hr teenaged C560XL. When it was repainted a couple of years ago they found lots of corrosion, and quite a lot of money is being spent on maintenance.
The owners are quite sensible and are trying to replace it with an XLS+ but it's not really worth very much...
At my local airport there are a couple of Rockwell Sabreliners and Lockheed JetStars regularly on the move...
There is a HA4T based at my local airfield too and it seems to have frequent technical problems - crew telling ATC they need to taxi back to the ramp to turn everything off and on again, etc. Shame, I quite like the design.