I am in the same boat. Basically my attempts at using ST with Vivint has been a fail.
My contract with Vivint ends this month. After numerous attempts and multiple partial successes, the Vivint panel became completely bogged down and barely functioning. I finally did a factory restore and had to call Vivint and get them to add my panel back into their system. I then added all of the 345mhz security devices back into the Vivint controller. Vivint has since upgraded my panel to 3.10.xxx and now I also have to call them to unlock the panel that I technically own.
My experience has been that Smartthings will recognize the locks and thermostats but as Isckk5 mentioned above, they will become unresponsive. When they do I have been able to “wake them up” by going into the settings for the device in ST (clicking on the gear in the top right) and then clicking done. Which seems to save the device and re-establish communications. This is quite frustrating and I am now ready to walk away from the Vivint control panel.
I am now considering the ADT rebranded 2Gig panel or to either the 2Gig GC2 or GC3 panel. I would prefer to self monitor or pay no more than 20/mo for monitoring.
Any help or suggestions are comments from personal experience with this combination would be appreciated.