I was also going to suggest looking at the ADT/smartthings security panel. It gives you everything you get with the other smartthings hub home automation systems (Including the cloud dependencies and lack of reliability), But the security piece is Essentially a separate silo and fills in a lot of the gaps that the other smartthings model lines are missing. Including local operations for the dual logo devices, which are the ones used for security.
It looks to be a decent low-cost security system. And it does have the advantage that while you cannot use the single logo SmartThings Sensors to trigger a call to the ADT monitoring center, you can use the dual logo sensors in home automation routines as well as the security system. So it’s just much cleaner integration than pretty much any other method.
I’m not saying it would be the best one for you, but I would definitely put on your candidate list. 
Here’s the main community discussion thread for that system if you want to talk to other people who have it:
Abode also seems to be a good security system candidate in the low-end range. They have an entirely new model scheduled to come out in July, so That’s just something to be aware of.