Yes it is. Kawasaki is regarded in commercial landscape as top quality equipment alongside Shindaiwa, Honda, and Tanaka. All japanese brands. Kawasaki is in the same class as Honda mower engines, in terms of durability and reliability. Alot of japanese manufacturers use the same components (bearings, seals, tanks, electronics, pushrods, etc) in manufacturing (Japan is an island, not much room for competing factories).
BTW, the FJ180V utilizes a forced lubrication system. That is better than the comparable splash lubrication used by Honda. It has an oil filter on it. I would get it over the Honda.
I own a Honda mower and it is top-notch quality and runs like new after 10 years of service. I think the Kawasaki's are built even better (commercial grade as opposed to Honda's residential grade).
What mower were you looking at that has this engine?