Instruct: Classify Amazon reviews into positive or negative sentiment
Query: 2 Swann DVR4- Alerts

First DVR4-Alert was defective, it would not recognize any hard drives. It was exchanged for another DVR4-alert, this recognizes the hard drive but gives a hard drive failure error most times when recording after a few minutes. Units are not reliable enough for 24/7 security. Save yourself a head ache; spend more money and buy a better DVR.