Canon SD 600 vs SD1000

Hi guys,
A question for you, if I may, about Canon's Sureshot line. So, a
buddy of mine bought an SD600 and seems really happy with it. Good
pics, surprisingly good video from a band's gig he recorded in a club
setting. I'm in the market for a digital camera and thought I'd just
pick up the same thing. Easy recommendation from someone I know, plus
reviews are really strong fro this one.

Now I see that there is the SD1000, and I'm wondering, is this just
the latest upgrade, the same camera with some newer modifications?
Also, if it is the next model up, is there anything, featurewise, that
has actually decreased in quality since the 600 model? I'm torn on
which way to go, and I'm looking to buy one within the month. I don't
mind gaining a few features (provided they're actually useful of
course), but I also don't want to lose anything that's been working
just fine on an earlier model. If it ain't broke, don't fix it,
right?

Any advice from you photography devotees out here is most
appreciated. I guess this would be a good time to ask about any
comparable models from any other manufacturers. The Canons are small
and have a great reputation, but amazingly, I know there are even
slimmer cameras on the market.

Thanks so much in advance,

best,
Ben