I told someone on here, I think Alpha, that I will let them know what I thought about AutoChart. I've been making maps for about 6 months now and it's taken a lot of time (both on the water and behind the computer), but it has been worth it.
I have a Navionics card and it has been great and I still continue to use it in areas I haven't mapped, but the AutoChart map I've made has much more detail. Below is a comparison I've put together between Navionics, Navionics SonarCharts, and AutoChart from a few points I've mapped.
I've fished the point on top, but never fished the bottom point much because it doesn't look as good on the Navionics as what I mapped.
The only thing I wish you could do if overlay the two. I have a 998 and I believe you can do this on the ONIX which I will be getting. In most cases there isn't much difference in the maps, but I have found spots on my map that aren't on the Navionics and I have caught a ton of fish of them.
The last thing I will say is the program is not easy to use. I think I've gotten it down, but you have to fix false readings and areas you've lost GPS signal. It has been worth the money though.