I've had one ever since I opened 20 years ago. We've been through a few of them, only because my husband is a gadget type of guy and upgrades every chance he gets.
The last one we had was this one...
http://www.costco.com/Lorex-Eco2-16-...100002500.html
We no longer have it only because my husband has since upgraded again, and I have no idea what we have now, so I will have to ask.
I will say the one in the link above was wonderful and no issues. I've had full systems as low as $500.00 on up to the thousands, and the cheapest ones did just what I needed.
I could never live without one because we have had one for so long, I would be lost without it. My cameras show the entire perimeter of my home, comings and goings, and the daycare room. Only once in the 20 years that I have had it, did I have to remind a parent that a situation that she caused was recorded.
I highly recommend anyone doing daycare to have a surveillance system if they could.