I have had ADT in three houses and was happy with their service. It was as someone pointed out more expensive and time consuming to install than I expected but all the houses were over 100 years old which probably presented extra challenges.

I also have the big, protective dog and gun which thankfully at this time I would still be able to operate if needed. I'm home alone most nights and can't imagine not having my mutt by my side although he has been 10xs more expensive than any of my ADT systems.