I prefer CSF over APF, and it all depends on how you set it up imho. Just don't use CC based blocking if you want a low impact. CentOS is pretty straight forward for both, afair they both have a install script, but I haven't used APF in quite a while. Switched to CSF and haven't looked back. If you google for installation tutorials, I am sure you will find quite a few. In closing though, I find CSF has more "features/options", and a bit better control, but its all about personal preference.
In my experience, APF has had odd issues after running for a prolonged period of time and begins to block legitimate requests until it is restarted. Give CSF a shot, I'm sure you'll be happy with it. If you are using CPanel on a cloud server, there is a gui for configuring CSF that APF lacks.