I've had Vivent for about a year and a half. At first it was real cool being able to control your house from a smartphone. But the equipment they install is junk. The service/monitoring is overpriced IMO. Hindsight being 20/20, I would have not installed a Vivent system.
My buddy has it. He seems to like it but the monthly is pretty high. I believe he's paying almost $100/ month. Kinda cool the things he can do though. Turn lights on, unlock his front door, etc.