From my understanding the Iris sensors will work with the ADT hub but only for home automation aspects for the security side you have to use all ADT propriatery sensors, smoke detectors, sirens, and presence sensors I don't believe the ADT security has a Geo Fencing option.
On the sensors, you are partially correct.
IF you are going to have ADT professional monitoring, then yes, only the ADT Smartthings branded equipment is compatible. However, and I have already set up my system and tested, the Iris 2nd gen contact sensors will trigger an alert event in the self monitored mode no problem, same with the motion sensors... So basically, if you are planning on professional monitoring, go with all ADT Smartthings devices, if you are planning on self monitoring, go with ADT Smartthings / Iris / whatever is compatible devices...
My setup is a bit of a kluge, but it is working so far. I have the following.
ADT Smartthings Home Monitoring kit.
ADT Smartthings Door and Window Detectors on all access points, window casements, doors etc...
Iris 2nd generation contact sensors on "sensitive internal" access points I want to monitor.
Iris 2nd generation motion sensor in an area we want additional monitoring.
2 @ Utilitech indoor sirens
2 @ Ring Spotlight Cameras
Ring Floodlight Camera
Ring video doorbell 2.
Iris 3rd generation ZigBee smart plug.
Phillips Lightify hub and bulbs, one internal room, and patio lights
Amazon Echo Dot with Alexa Guard.
This whole thing is a bit of a kluge, but let me explain. The sensors all work well, integrate at least for self monitoring seamlessly. The Utilitech sirens drop right in no problem and offer both siren, and light function, both huge attention grabbers.
What I have figured out thus far is the ring cameras light and motion sensor functions tie into Smartthings, I am still trying to figure out the siren and video feed functions, but for now I have to use them from within ring.
The Iris smart plug goes right in with no problems. And it is used as expected within alerting.
The lightify has yet to be integrated, but I expect to be able to use it to turn lights on and off depending on various needed responses. I would think individual bulbs can be added to created groups, such that say the 2 bulbs in the porch light are one group called "Porch Light" and the 2 bulbs in the master vanity can be grouped in a group called "Master Vanity" etc...
Alexa Guard, if you are unfamiliar, allows you to use Alexa / Echo devices to listen for smoke and CO detector alarms and then triggering a response such as a push notification, a text, an IFTTT trigger etc...
Areas I need to dig into to complete my configuration.
#1. How to handle IFTTT triggers from Alexa Guard to trigger an alarm from within Smartthings.
#2. How to configure / use Ring sirens from within Smartthings. I suspect this would be via IFTTT.
#3. How to receive, record, and work with ring camera videos from within Smartthings.
#4. Panic button function from within the ST app.
I am getting a lot closer, and further along than I was with Iris (lightify integration, Alexa Guard etc...) So unless Samsung wants to lose me, and my frequent tech dollars as a customer and goes and kills ADT Smartthings, I am good to go...
So after a lot of searching, I am trying VeraSecure. They have packages at a discount and help from customer support for IRIS by Lowes users. I have been switching over. My First Alert Fire & CO2 and Schlage lock went seamlessly. I have been working with them and have started to get my door and window sensors to connect, it takes a bit of work, meaning maybe doesn't happen on the first time and it seems that removing them from IRIS first is best. I have 14 sensors and was not reimbursed for them since the are Smart Things compatible, I am not interested in ADT. They are working on getting the cameras on but becasue of proprietal software, not happening easily. I was reimbursed for both of my cameras.....The did have a monitoring platform that they are in the process of updating, they say it will be available soon. It is very reasoably priced. The platform for making rules and notifications are similar to but not the same, unfortunatley as IRIS but nothing is perfect. I have to say that the customer services and sales people that I have worked with at Vera have been really amazing and patient. I am not very techy. www.getvera.com
Just as an update. I have now been able to pair 3 G2 iris smart plugs. On the back of the device it says Z wave plus. Again doing some research I learned that it has both Zigbee and Z wave properties. It pairs at a Generic Zigbee device.
I went to Iris because we don't like monthly payments forever.
So my preferred choice is Home Assistant to keep things off the cloud with it's inherent security issues. The learning curve is pretty steep but not undoable. Also, if something happens to me, I don't want to leave my wife with shomething that she would not feel comfortable supporting.hr
I looked at WINK, but the hubs are not available for a reasonable price, when I looked.
I settled for SmartThings. yes, it is cloud based, but it seems to work with most of the devices I already have. No continuing fees, good community support, official support is slow to non-existant depending on who you ask. I got the V3 hub, that is either ethernet or wifi connected, and it does support z-wave and zigbee 1.2 (not the 1.0 old devices).
The hub was about $60 or so. It did take be a bit to get everything setup, but so did Iris back when. I find automation more cumbersome than Iris, but it is just my way of thinking I believe.
I also installed a Home-Assistant hub to play with. It isn't to hard. But it supports wifi devices much easier than z-wave or zigbee. It is ultimately flexable and a very active user community is there. You can make HA (HomeAssistant) and SmartThing cooperate, so that is what I am doing now.