Manual IK or Rigify?

Being a bit new to IK I’m obviously missing a whole load of knowledge and I realize this is a very general question, but do all you lovely animator/modelling people prefer to manually build your IK rigs, or use Rigify?

Although I know little on the subject I can see from a YouTube Rigify does a huge amount of work, but where are the pitfalls? Or, have the pitfalls been filled up?

Thanks.