Totally redundant. You bought yourself an excellent zoom, as good as the previous one in terms of overall quality, plus with the greater range of focal lengths... What exactly "died" in the 28-70mm - chip, zoom mechanism, focus mechanism...? Or you dropped it (broke it)?
I have the 28-105mm 3.5-4.5 as well and I bought it after much research and reading what a wonderful lens it is in terms of IQ. So far those reviews have been true and I am glad I got a copy.
I also have the 18-70 AF-S lens and the 28-105mm is definitely much better than that lens. Never had the 28-70mm but had the 28-80mm D lens.
I say you have a great lens.
I also recommend the 35-105mm "D" One touch Zoom. Very sharp and a beautiful warm image.
I have the 35-105D.Not as good as either the 28-105 or 28-70mm.IMHO.
My 28-70mm 3.5D died and I bought a 28-105mm 3.5-4.5D.I loved the first lense and am enjoying the new one but wonder if anyone thinks there is a difference in IQ between the 2 other than reach?Is buying another 28-70mm totally redundant?