I had the same initial problems, but now run it continuously on three
different computers. It is slow due to the limitations of the downloads, but
the screen re-writes are also slow.

It is great for filing flight plans, and the airplane modeling is also well
developed. Overall, it is well thought out and does the job. It is clearly
superior to Jeppesen's product, although I have both.

Except for the slowness, all of the other features like the flight plan,
terrain mapping, alerts, TFR's, etc, are very contemporary. My copies do not
lock up or crash, and I suspect that this is due to their online service
that downloads updates and fixes bugs automatically. I leave it running all
the time, so I can take a glance at the radar (when I wish I could be
flying). It has never locked up, and this has been for weeks at a time.

I use it extensively, and as I learn more about it, I find myself looking at
ADDS and the Jepp software less and less.