As mentioned above, I have only run a hopper through it since purchasing and other than that it has been sitting in one of my gun stands on my shelf. But I would have to say the shot count speaks for itself, it hasnt had more than 3 and half cases of paint run through it.
I haven't serviced the marker purely on the basis it worked fine when I bought and haven't had chance to use it since. However if my research into the marker is correct and this is the marker purchased from Foot you can gurantee that it has been looked after.