Squeaking noise usually comes if the mechanic use his dirty / oily hands on rotors.
Also copper antiseize should be applied on the backing plates of brake pads or where they contact with metal but finding copper antiseize is really difficult so one can use hi temp Silicone grease OR brake purpose grease on the backing plates also to avoid that and proper smooth brake operation. Never use normal grease that will only make the situation worse.
I haven't encountered any problems with frixa brake pads though..