I have seen a few PF's headsculpts that looks ok, mainly robots, monsters, and nonhumans, but nothing as good as some of the best Hot Toys headsculpts, IMO.
I like the Hellboy PF based on the promo pics, haven't seen it up-close though, but from far away most PF's looks ok, then another story up-close.
The paint is the biggest issue I have with the PF's, but the form is also off on many of them. They just look cheap and cartoonish to me. It's not enough for me that the sculpt unpainted might be good, but the final product altogether must be.
The PF's obviously sell well so that means that many people like them. In the end it's just personal preference and taste that matters.