You MUST remember that the dealer service departments see the ones that give trouble. They do NOT see the zillions of them that just keep rolling down the road.
Aluminum head engines are prone to head gasket and head problems. No manufacturer is immune to this.
When you read about achilles heel type problems here or anywhere else, it can easily sound like every single car built of a particular model experience this particular problem. In reality if 12 or 15 percent of the cars of that model experience that problem, it would be an EXTREMELY high percentage. The dealer people see all of those and it can easily sound like you are destined to experience that very problem on your car. In reality, the odds are heavily in your favor that you will not.
Listening to one brand dealer say that they see very few problems with their Double X 5000 model versus another brand dealer saying they see lots of problems with the Excelsior 500 is not very scientific data gathering.
The supposedly "independent" research firms such as J.D. Powers is not very meaningful either. They are influenced by the car manufacturers and skew data to a point that it is meaningless.
Have a great day,