I ordered this DVR because it was the best, but to tell you the truth I would have been just as happy with the model below this one. This really was commercial grade with a bunch or features i wont use. But it is cool to watch the playback of the video. and they made it very easy to copy the info from the hard drive to my USB Stick
My School district has a modest 45 Bus fleet, After going back and fourth we were finally able to find the exact system we needed to keep the kids and drivers safe. We put 3 cameras on the outside of the buses and 2 cameras on the inside and were able to record and play back all of them. They have been operational on our fleet since February of this year and other than a small fight with a few kids we haven't had to go into the recording but even digging up that recorded fight was quick and easy. i highly recommend using these systems over the SD card version just because it got massive recording potential and from my experiencing testing both models i feel the Hard Drive system is a little more heavy duty.