Anyone familiar with LinksKey?

No idea why, i'm guessing its nice and even number. 4,8,16, same with NVRs etc. You dont really see 5 or 9 channel NVRs anywhere either..

I've not heard of LinksKey (but at least they've been on the business for almost 30 years), according to the manual the switch looks good, probably worth testing if you have 8 cameras and you need a port for an uplink aswell. If you have less cameras, TP-LINK is a safe bet, we've used those in almost every smaller installation, though we've used the cheaper 4+4 (only 4 poe) model, 4 cams max per switch (to separate the network load from less powerful switches) and all switches + recorder + clients connected to a 1Gbps backbone.

Unmanaged switches are enough for most installations.
Managed would be nice if you really need to block ports, see power consumption per port, get alarms if the switch/a device disconnects or create VLANs etc.
 
If I needed an 8 PoE port switch I would get this one instead, as it is much cheaper, has the uplink port so you don't waste a PoE for it, and it has reviews to back it up: http://www.amazon.com/dp/B00H58P8RU

Admittedly this switch I linked is not gigabit. But really if you're going to go for a PoE switch with a single non-PoE uplink port that probably means you weren't planning to run more than cameras off of it, and 100 Mbps is fine for 8 cameras. You just connect the uplink port to a gigabit switch or router and from there all the camera traffic will be on a gigabit network where it has little impact on other network activity.