Summary: The switch crashes every day or so, making the computers behind it inaccessible. The issue is resolved by unplugging and plugging the power cord, but will promptly come back in another 24 hours or so. ZyXEL replaced once for me, but when I told them the replacement unit is still having the same issue, they insisted that it's because my own network configuration and refused to replace it again.
Summary: It is surprisingly tiny and nice looking metal casing. I plugged it into the network and it just work, well, mostly, as it turned out one of the port did not work. Not a big issue, so I kept it.