Personal opinion, but the best security system is the one that is dedicated to the job.
Abode isn't directly integrated with HE, but does have many IFTTT actions and IFTTT is supported in HE.
I've read many threads of people complaining about the reliability issues of using both SmartThings and HE as a security system. I just personally feel if a light doesn't come on, I can look at it and say "that's weird" and then try to figure it out. But if an alarm system doesn't trigger when it should, or triggers unexpectedly in the middle of the night, THAT is completely unacceptable to me.
Have not read complaints about the Konnected system. I don't monitor those topics closely though, since I don't have an existing wire system, so that doesn't apply to me.