I own two 2012 RT Limited’s both purchased this spring. Full season of riding with no issues. One has 31,000km the other 26,000km.
Reliability in my view has a lot to do with how things are maintained. If you keep up with the general maintenance, do regular oil changes, etc you should see many years of use. Rotax are very good motors with a proven track record.
One thing to be aware of is make sure you regularly check the engine oil. The 998’s do use a bit of oil and need to be topped up between oil changes. This is nothing to be concerned about, it’s just the way they are.