It's been pretty good. It has greatly reduced the MAV symptoms, although not completely eliminated them. And ad an anti-anxiety drug, it's also been quite soothing, in general - so even when I have episodes of MAV symptoms, they don't make me feel nervous.
The downsides are dry mouth and constipation, but both are manageable. Also, I think that high doses can be dangerous for the heart, so you might want to discuss that with your physician if you get above 100 mg/day.
Overall, I would definitely recommend sticking with nortriptyline for a while, if you can tolerate any side effects you might experience.