The newest hub has a few enhancements over the C5 hardware revision.
One is that it has external antennas. Personally this doesn’t appeal to me but many have found that their devices connect more reliably to the hub with the external antennas on board.
Another is that the C8 has the latest z-wave chipset, the 800 series. And the latest zigbee profile, zigbee 3.0.
Do you have any z-wave plus devices with the 700 or 800 series chipset? Or any zigbee 3.0 devices?
The C8 also has a built-in WiFi radio, meaning it can now make either a wired connection to your LAN with the Ethernet port, or wirelessly with the new WiFi radio.
However, the saying “if it ain’t broke, don’t fix it,” may apply here.
Most people are able to migrate from an older hub to a C8 using the included migration tools without incident. But sometimes issues will come up during or after the process of hub migration and the user should be prepared to troubleshoot those issues.
Edit: here’s an announcement that summarized some of the C8 hub’s new features at the time it was released.
