The two big features that you'll be missing on the C8 vs the C8-Pro are the "HomeKit Controller" integration and Z-WaveJS support. The C8 still supports Z-Wave via the older Z-Wave ZIP stack.
The C8-Pro has twice the RAM and a faster CPU. The above features require the beefier hardware which is why they are not available on the older model hubs. For a small 30 device system, the C8 should be an excellent choice.