The Google study is very interesting, but this app has saved several of my clients from much distress. Yes, Apple's Disk Utility monitors the same SMART parameters, but the value of this app is in the notification warnings, both as on-screen pop-up boxes, and the ability to Email 3rd parties that a potential problem may be about to occur. When I got the Email notice about the SMART failure, I notified my client of the situation and they verified it in Disk Utility. The Apple Store had no qualms about replacing the drive since the computer was still under AppleCare.
A very useful application!
Thanks!!