First off welcome Colorado! Since I was the OP I'll share my brief experience researching and calling about the engines. First off let me say I did not buy the plane in question, though it was not due to the engine or anything else. I took a serious look at my mission, budget and hours flown and realized that rental was a far cheaper alternative. I'm not writing off ownership, but the price has to be right and the plane has to fit my needs and budget.
So on to your question: Jabriu engines have a mixed past. In Australia (their native country of origin) they had a seemingly high failure rate, which lead to a serious investigation (almost 2 years) and limitations during that time. This has since been cleared up, but the underlying reason was that A&P's were not trained in the eccentricities of the engine and were missing signs of wear. To quote the findings:
The failures experienced can generally be attributed to the maintenance practices, not necessarily poor quality of maintenance but… any deviation from the current Jabiru recommendations does appear to introduce conditions that can rapidly deteriorate the engine health to the point of failure. Hence, the current maintenance schedule (in particular 25hr oil changes) and the maintenance requirements for cylinder head inspections/maintenance per Service Letter JSL014 can be expected to provide for an acceptable level of reliable operation if they are adhered to with some vigilance.
So I take this as you (or your A&P) better know the engine of you can easily overlook issues. There also were multiple reports of overheating, both in Jabriu airframes and in experimental applications. Airflow to the rear cylinders was considered problematic and could cause overheating under hot/humid conditions, which in turn creates excessive wear issues. Jabriu has addressed some of these issues with changes to the lifters, baffling recommendations and changes, and better training for A&P's. It's my understanding they also redesigned the engines recently in an effort to correct past deficiencies.
All that to get to my point: I would not (and have not) discounted Jabriu powered aircraft in my search of a plane. I would however get a through inspection from an EXPERIENCED Jabriu mechanic before I would purchase one and understand parts and experienced A&P's will be lacking in the US. Also, if your into the Arion Lightning, Nick at Arion has a whole host of engine fitment options, including Lycoming, UL, etc. So if you are looking to build or even swap engines those may be options to think about. You will need to check on what you can and can not modify based on the way it was registered and airworthiness certificate. Most of all I'd recommend calling Nick Otterbach at Arion. They just were named the Jabriu engine support and repair shop for North America, so they will have experts in both the airframe and engine. I have talked with Nick on the phone a couple times and he is very helpful and very willing to answer any and all questions I've ever asked.