As @Mavrrick58 said, the ADT model hub is designed for security, the other models are not.
Even if you intend to self monitor, there are glaring deficiencies with regard to security in the other models since they are all cloud based.
Remember that the ST cloud has historically had at least one unscheduled outage every month, plus one or two scheduled ones, and often more. See the following thread for discussion and details:
Some of the most obvious:
Without the cloud, there is no way to arm/disarm the system. None. See the forums for discussion of how much the family enjoys having the siren go off because you come home with the system in armed mode and there’s no way to disarm it. 
Without the cloud, there is no way to get notifications, even on your own phone. None. Even more fun, the notifications may stack up and then come all at once when the cloud comes back online. 
Again, see the hub features FAQ:
If you want security features and you aren’t going to get the ADT hub model, you will be better off looking at other purpose-built DIY security systems like Ring, Abode, and Simplisafe. There’s a reason the security links on the ST site only take you to the ADT model.
If you don’t need security features, just Home automation, then the other ST hubs would make more sense than the ADT model.