If you're certain that you meet ALL CEC requirements + you don't have a criminal history or somethen,
then apply for CEC only. You don't need the additional cost for PNP, as the CEC class is a pass/fail system.
What that means is, if you meet all the requirements and pass security tests, you will get your PR approved for sure.
If you fail, you get rejected.
So if you meet the criteria, go for CEC, as it's bullet proof.