We neiew on soed to realise that both sides want to honor and glorify God by how they view salvation, but would also have to say that the viewpoints of calvinism in strictly the area of Sotierology seems to better fit the teacxhings of the scriptures...
Yes, I think both camps are trying to be faithful to Scripture and I think that, relatively, Calvinism can muster more passages to support it's position (which, of course, does not mean that Calvinism is correct).
Metzger is writing from a Calvinistic point of view to, it appears, appeal to like-minded believers. He is not defending Calvinism but instead is examining evangelism.