We have two on our Present 38, 2700 and 2900 hours. We haven't put many hours on them, maybe 150-200. Other than leaks the only problem has been a corroded injection elbow.
I did find a reference to some issues with intake valves. Seems they used two different suppliers and one of them had a tendency to drop valve heads. We did get an engine survey. One engine had been documented that the head had been worked on but I showed the engine surveyor what to look for on the other engine.
Also if you do your own work, there is a mistake in the manual for doing valve adjustments.