I have the new one (the PZD). I bought it to stick in my pack as a general purpose lens that gives me options when the lens selected for the day is specialised, e.g. macro or super-tele. I looked for a long time at the old version as a possible holiday lens, but was never really that impressed with it. I bought this one as soon as I saw it in the flesh. It is very compact. It does't claim macro, but the claim the old one made to that effect was specious. It's slow at f/6.3 zoomed in, but you can't have everything. I find the image stabilisation is very good, giving my Canons a run for their money. When I got it home I compared the sharpness with a Canon 70-300 IS (non L) and I couldn't tell them apart. I put it on my old 350D and it felt like a perfect match. With this combo I went to a daytime event and took these shots:
Zoomed out:
Being There by
strictfunctor, on Flickr
Zoomed in:

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Tim Costello by
strictfunctor, on Flickr
I'm quite happy with it.