I'll also say that their equipment is pretty cool, but their tactics are borderline criminal. One of their sales guys knocked on the door and told me he was from my alarm company, and was there to upgrade my equipment at no cost ... When I said I didn't use Vivint, he said, "Oh, well, we bought your old company, XYZ, and your equipment is now obsolete. I need to upgrade it or it soon won't function properly."
He then pulled out photos of my exact equipment, and showed me the new stuff ... I knew he was full of it, but our neighborhood had experienced several break-ins and I wanted something a bit more.
As I said, the equipment was really nice and seemed to do everything they said it would. But the ironclad contract (four years, I believe, at $40-50 per month) made me pause. Fortunately, we ended up selling the house later that year and the new owners agreed to take over the contract. Otherwise, I doubt they would have let us out without paying them the balance owed.
In short, VERY sketchy sales tactics (to include outright lying to your face), but nice, state-of-the-art equipment with LONG contracts ... YMMV.