It’s even worse than that. The marketing implies one thing. The product terms of use say something entirely different:
https://www.smartthings.com/guidelines
Data accuracy and consistency from SmartThings sensors, including those provided by SmartThings directly, resold by SmartThings, or supported by SmartThings, is not guaranteed. Therefore, you should not rely on that data for any use that impacts health, safety, security, property or financial interests.
ADT’s fine print is quite different on their systems. They do say the system isn’t perfect, but in most cases for their professionally installed systems they also offer to pay up to $500 toward your insurance deductible if you do have a loss while the system is armed.
BTW, I wouldn’t consider the existence of the new ADT/smartthings system an example of bait and switch provided the company’s marketing is changed so that consumers with a prepurchase interest primarily in security are directed towards the ADT product from the beginning of their research. I agree absolutely that if they keep the current marketing, someone buys the $99 hub, complains to support, and is then told that they should instead buythe ADT product, that would be inappropriate.
There’ve been a lot of new offerings in this space recently. Abode has been out for about a year and seems to be pretty solid, although it has a limit on the total number of IOT rules and devices which doesn’t match my own needs.
Nest and ring both just announced new packages.
In the community discussion about the nest offering, I listed some of the things that I consider a minimum for a purpose built security system. The new ADT/SmartThings package looks like it will also meet most of these points (still don’t know about the camera), so a lot of new players in the space.
What I didn’t mention in that post, although I have elsewhere, are the issues you brought up about secondary users. I agree those are absolutely critical, and so far we don’t know how any of the systems will handle them. One of the problems that people have run into in the past with the current SmartThings system is that once you give someone access to the account, if you remove them again they will still have access until the time that they log out and try to log back in again. We actually had a community member with an abusive former roommate who had this problem. 
So I’m hoping that will also be changed with the ADT offering. But we will just have to wait and see.