You're not going to get a lot of additional feedback on JBA from anybody. KangkeUSA just started importing them last year, and that thread I referred you to started because an RC journalist (Ed Moorman writes engine reviews for RC Report) was curious about them but nobody had reviewed one yet.

That thread detailing Ed Moorman's break-in and testing is the most comprehensive source of information on the JBA .56 that is currently available. The engines seem powerful and reliable, and KangkeUSA is a good company to work with regarding warranty and/or customer service. If you buy a JBA engine, however, you'll likely be the only person at your field with one.

Hopefully, once word gets out on how good of a value these engines are, they won't be such an unknown product. If venturing into slightly unknown territory makes you nervous, buy an O.S. .46 AX and don't give it a second thought.