Received my Yi camera last week and have been testing it over the weekend. Overall i'm very happy it, the quality is spot on and can pick up most details on things like cars & people.
I have it sat looking out the bedroom window overlooking the driveway, had to turn motion alerts off as i was getting tons of notifications even on the least frequent setting. Problem is there's a fairly busy road at the bottom of our drive and even though i've adjusted the motion area detection, it picks up cars going past, and next doors cats seem to know its there and enjoy walking past every few mins

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It does record 24/7 to sd card and i can go back through and review previous footage throughout the day, not signed up to the cloud storage yet but think i will as planning on getting another couple of cameras for indoor and the back of the house.
Shame it doesn't have facial recognition etc but what it does do, it does well. But overall for the price i'm really pleased with the camera and its features.