This is a wonderful, stable add-on for X-plane 12. I've put many hours on it in the few days I've had it and have not experienced anything broken except for a few mouse click issues (like most add-ons). This jet feels great, authentic, and the systems just work. I will say though, when flying well north (above the arctic circle) the INS does not track well with the course plotted. Having flown there myself using classic INS moons ago, I know you get some very strange effects as you go north. Over the pole was quite interesting IRL with the aircraft symbol flying backwards on that older system, so I'm not sure if this is a fault or perhaps very precise reproduction of classic inertial system drift and vulnerability up north. In any event, its not a hard aircraft to fly if you are familiar with Boeing products. It is worth the price I paid for it (full).