Yes. At it's inception, the NCEA was regarding as lacking integrity. There were also concerns over the fact that it wasn't as widely recognized as Cambridge. In recent years however, the NCEA has proven that it can provide top level academic achievement to students who work for it. The NCEA has really improved since it's inception.
No, NCEA is not better than Cambridge, because Cambridge examinations do a better job of giving an in-depth assessment of a student's abilities. The NCEA exams are more rigid. They tell who is the best achiever, but they do not really reveal the strength and weaknesses of each individual student. The Cambridge examinations are more thorough.