It has its annoyances, for sure. But it is usable. But when it goes wonky, I just cancel IFR. I had one over the weekend where it wanted to send me up to 17,000ft in the JF Arrow. I was maybe 20 miles away at the time at 9,000ft. I cancelled IFR, and flew on till I was around 5 miles away. I then used the option to re-file the previous IFR plan, and it wanted to send me up to FL170 again. 