I am on a bit of a tight budget and as much as I'd like to get the upgraded model I can't afford it at present. Added to this I have seen a couple of second hand models of the newer version for sale but have been dubious when I've gone to take a look at them. I've heard a lot of good things about this lens. Anyone able to speak from experience and shed some light on the good and bad points about this lens? It would be greatly appreciated.