Pick your poison. People have gone both ways, from Super Ten to Africa Twin and from Africa Twin to Super Ten. If you're more off pavement inclined, you'll appreciate the AT more than the ST, but the ST can still do off pavement very well. If you're more pavement/gravel fire road oriented, the ST has more benefits.
Nut shell view with limited high points -
AT - 21/18 wheel sizes, lighter weight, Honda reliability, still good power and ok road manners.
ST - Shaft drive, tubeless tires, 19/17 wheel sizes for more tire options, CC and better road manners, but still off pavement characteristics.
Lots of aftermarket goodies for both. I've not ridden a AT, but the owners I've talked to that have ridden both or came from an AT to the ST have mentioned that the AT is not as stable at highway speeds as the ST. Possibly due to the same wheel sizes that give it an edge off pavement. Because I sell Rumbux for both, I've had a nice opportunity to talk to owners of both since the AT came out.
Personally, I'm more road than off pavement, and do long distance touring, so don't want to give up shaft drive and tubeless tires. I was surprised when I read that the AT had tube tires. That's almost unheard of on a Big Trailie these days. Makes me wonder if Honda wasn't just too cheap to license someone's Tubeless spoked wheel design?