I've been thinking about one of these for my back yard - it gets pretty dark here and the walk from the house to the workshop in the wee hours has me thinking about wildlife.
Security isn't an issue, but bears are common around our neighbourhood. I've surprised a couple in my driveway over the past few years, and that back yard sure is dark...
On the flip side the bears won't come into the house, and the kids will get woken up in terror every time a raccoon or deer walks by (which is pretty much nightly where we live).